Cristian Roldan inspired Seattle to a 3-1 win over the Galaxy in California.
Roldan opened the scoring in the 12th minute, completing a fine team move by getting on the end of a Jordan Morris cross.
Morris doubled the lead seven minutes before half-time, finishing after a lovely pass from Nicolas Lodeiro.
Roldan produced a clinical finish from a Joao Paulo pass to make it 3-0 just after the hour-mark, with Seattle winning despite Sebastian Lletget's late goal for the LA Galaxy.
It marked Roldan's third multi-goal game in MLS, and two have come against the Galaxy.
Seattle are top of the Western Conference, equal on points with the Portland Timbers, who recorded a 1-0 win over the Vancouver Whitecaps.
After joining Inter Miami following his Juventus release, Higuain had a tough debut in a 3-0 loss to the Philadelphia Union.
Higuain hit the outside of the post with a bicycle kick and later put a penalty over the crossbar.
Anthony Fontana, Ilsinho and Brenden Aaronson scored for Philadelphia, who are second in the Eastern Conference.
Higuain, meanwhile, has failed to convert his past four penalties in all competitions.
Eastern Conference leaders Columbus Crew fell to a 3-1 loss to Toronto.
The New York Red Bulls thrashed the Montreal Impact 4-1, the New England Revolution beat DC United 2-0 and Chicago Fire overcame Atlanta United 2-0.
Minnesota United played out a goalless draw with Real Salt Lake, while Dallas' clash with Orlando City also finished 0-0.
The San Jose Earthquakes ended a nine-game winless run by beating Los Angeles FC 2-1.
Trailing 4-2 heading into the 90th minute, former Manchester United and Italy forward Giuseppe Rossi reduced the deficit for RSL in Portland – his first MLS goal.
And Sam Johnson completed the stunning comeback against the MLS is Back Tournament champions in the fourth minute of stoppage time.
In a wild showdown, the Timbers opened the scoring through Diego Chara in the sixth minute before RSL's Corey Baird restored parity 13 minutes later, but Jaroslaw Niezgoda's effort within two minutes ensured Portland led 2-1 at half-time.
After Real Salt Lake equalised again, this time courtesy of Damir Kreilach three minutes into the second half, Portland took control of the contest.
Sebastian Blanco's stunning effort with 20 minutes remaining and Felipe Mora's effort five minutes from time seemingly had the Timbers on track before the hosts capitulated.
The Timbers are fourth in the Western Conference, a point above RSL after seven matches.
LA Galaxy beat San Jose Earthquakes for the first time since 2018 thanks to their 3-2 triumph in the California Clasico.
Sebastian Lletget's 82nd-minute goal settled the five-goal thriller after the Earthquakes had led 1-0 and 2-1 against the Galaxy.
After posting just their second win in the regular season, the Galaxy are ninth in the west, while the Earthquakes are eighth.
In other results, Philadelphia Union crushed DC United 4-1, New York City accounted for Chicago Fire 3-1, Dallas defeated Minnesota United by the same scoreline and Orlando City also topped Atlanta United 3-1.
FC Cincinnati played out a 0-0 draw with Columbus Crew, New York Red Bulls drew 1-1 against New England Revolution, while Western Conference leaders Sporting Kansas City were held to a 1-1 draw by Colorado Rapids.
Alan Pulido, Luis Martins and Daniel Salloi all scored within 16 minutes as KC raced to a 3-0 lead. Salloi's classy volley took his tally to nine goals this MLS season.
Israeli midfielder Gadi Kinda added a fourth in the 58th minute with Graham Zusi getting his second assist, before LAFC got a consolation from Danny Musovski.
The win lifted Sporting KC past Seattle Sounders who conceded in the 90th minute to draw 1-1 at home with Dallas.
Fredy Montero had put the Sounders ahead in the 72nd minute with a set-piece header but Dallas equalised from Franco Jara's 90th-minute close-range strike.
Sporting KC are ahead of Seattle on goal difference, with both sides having 33 points, although the leaders have a game in hand.
LA Galaxy are third following a 1-0 victory over Real Salt Lake, secured by Efrain Alvarez's cool 53rd-minute winner.
Eastern Conference leaders New England extended their unbeaten run to five games with a 0-0 draw against Nashville, who slip to fourth despite the result.
The draw also extends Nashville's undefeated streak to nine games.
Former England international Kieran Gibbs netted a 66th-minute equaliser to earn Inter Miami a 1-1 draw away to fellow Florida outfit Orlando City. The goal was Gibbs' first in the MLS.
Philadelphia Union ended their three-game winless run with a 3-0 victory over Toronto after three first-half strikes.
Ola Kamara and Yordy Reyna both netted doubles as DC United won 4-2 over Columbus Crew.
Tomas Pochettino scored a first-half brace as struggling Austin won 3-2 over Houston Dynamo.
Chicago Fire and 10-man New York City played out a goalless draw, while New York Red Bulls and Cincinnati also ended 0-0 and Portland Timbers drew 1-1 with San Jose Earthquakes.
Sergio Santos netted three times as Philadelphia crushed Toronto 5-0 at Subaru Park on Saturday.
The result equalled the Union's biggest ever win and Toronto's largest defeat, as per Opta.
Philadelphia needed until the 27th minute to get going, Sergio Santos heading in a wonderful cross from Kai Wagner.
Just six minutes later and the hosts doubled their lead, Mark McKenzie heading in from close range after a corner.
Jamiro scored a spectacular third for Eastern Conference leaders Philadelphia in the 56th minute, his 20-yard effort going in off the underside of the crossbar.
Sergio Santos put away two more to complete his hat-trick – the fourth in the Union's history and first since C.J. Sapong in May 2017.
Western Conference leaders Sporting also enjoyed a fine win, thrashing the Colorado Rapids 4-0.
Alan Pulido, Andreu Fontas, Gadi Kinda and Gerso Fernandes netted in the victory.
Leandro Gonzalez Pirez's 89th-minute winner saw Inter Miami – without the suspended Gonzalo Higuain – edge Orlando City 2-1, while DC United overcame Atlanta United 2-1.
New York City recorded a 3-1 victory over the Montreal Impact and the Vancouver Whitecaps were too good for the San Jose Earthquakes 2-1.
The Chicago Fire and New York Red Bulls drew 2-2, Minnesota United edged Cincinnati 1-0, Houston Dynamo and Columbus Crew drew 1-1 and Real Salt Lake and Dallas played out a goalless draw.
Sporting claimed a 2-1 win over Minnesota United at Allianz Field to pull clear atop the Western Conference.
Michael Boxall's 55th-minute own goal proved decisive as Sporting claimed a fifth win in six MLS games, going four points clear of second-placed Minnesota.
Gadi Kinda got on the end of a Jaylin Lindsey cross to give Peter Vermes' Sporting a 12th-minute lead.
Minnesota were level just after the half-hour mark, an unfortunate deflection off Lindsey leading to an own goal.
But Boxall turned a cross into his own net 10 minutes into the second half for what proved to be the winner.
Toronto recorded a second win in four days over the Vancouver Whitecaps with a 1-0 victory.
Richie Laryea's low finish in the 15th minute was all Toronto needed, getting back to within a point of Eastern Conference leaders Columbus Crew.
In the day's other games, Cincinnati and DC United drew 0-0, while the Houston Dynamo's clash with Dallas also finished goalless.
Johnny Russell's 79th-minute goal gave Sporting KC a 2-1 win away to Seattle Sounders, locking up a play-off spot for the second-placed team in the Western Conference table as Russell netted for the seventh straight game.
Colorado also are in after defeating Portland Timbers 2-0 behind golas from Dominique Badji and Diego Rubio.
The Seattle loss ensured New England, who face Orlando City on Sunday, will finish atop the overall table. The Revs are on 69 points, 20 points clear of Philadelphia and Nashville in the Eastern Conference and 11 clear of Seattle overall.
Nashville had a chance to clinch the play-offs with a win but fell 1-0 to Philadelphia Union on Kacper Przybylko's first-half penalty.
Inter Miami got a goal and three assists from Gonzalo Higuain, while his brother Federico also found the net in a 5-1 rout of Cincinnati, who lost their ninth in a row.
Toronto dealt a blow to rival Montreal's play-off hopes as Jozy Altidore's free kick in the fifth minute of stoppage time secured a 1-1 draw after Sunusi Ibrahim had netted in the 55th minute for the visitors.
Minnesota and LAFC also finished at 1-1, as did San Jose Earthquakes and Vancouver Whitecaps.
New York City crushed DC United 6-0 and Sean Nealis' 87th-minute goal lifted New York Red Bulls past Columbus Crew 2-1.
Sebastian Lletget's brilliant 83rd-minute equaliser gave LA Galaxy a 2-2 draw with Dallas, while Chicago Fire downed Real Salt Lake 1-0.
Sporting KC scored twice in the closing stages to see off the Galaxy in Los Angeles and leapfrog Seattle Sounders atop the west.
The Galaxy were without former Manchester United and Real Madrid star Javier 'Chicharito' Hernandez after he was a late withdrawal prior to kick-off.
Chicharito scored a brace against San Jose Earthquakes last time out to take his total to 10 goals in 10 games this season – only four players have scored more through their first 10 appearances in an MLS campaign, Carlos Vela (Los Angeles FC) in 2019, Chris Wondolowski (Earthquakes) in 2012, Landon Donovan (Galaxy) in 2008 and Roy Lassiter (DC United) in 1999, all with 11 goals.
The Galaxy felt his absence as visiting Sporting KC – who have scored an MLS-high 24 goals in 2021 – won late thanks to Johnny Russell and Khiry Shelton.
Russell broke the deadlock in the 81st minute with a looping header and Shelton made sure of the points in the fifth minute of stoppage time.
Sporting KC and Seattle are level on 26 points, but the former top the Western Conference with more wins, though they have played a game extra.
The Sounders tied the MLS record with 12 unbeaten games to start the season following their 1-1 draw at Colorado Rapids.
Alex Roldan put Seattle ahead four minutes before half-time, but Colorado's Michael Barrios restored parity approaching the hour-mark.
Elsewhere, lowly Dallas and Vancouver Whitecaps played out a 2-2 draw.
DC United appeared on track for victory following Nigel Robertha's ninth-minute opener away to New York City on Sunday.
That was until New York City – who have never lost a home match to DC United (W5 D2) – rallied, with Keaton Parks equalising in the 84th minute after flicking home a header from Maxi Moralez's corner.
Thiago then took centre stage in the 95th minute – the Brazilian embarking on a spectacular solo run from his own half, breezing by his opponents and finishing decisively.
New York City have scored in 21 consecutive MLS games (including playoffs). It is the longest active run in the league and longest in club history.
With the win, New York City are fourth in the Eastern Conference – six points adrift of leaders New England Revolution, who lost 2-1 to Dallas.
The Revolution were unable to restore their five-point lead atop the table following Ricardo Pepi's brace for Dallas.
Homegrown star Pepi was the hero for Dallas, who snapped their six-game winless streak by topping the Eastern Conference leaders.
In other results, Atlanta United and New York Red Bulls played out a goalless draw, while Austin and reigning MLS champions Columbus Crew also drew 0-0.
Sibling pair Diego and Yimmi Chara were among the goals as the Timbers – unbeaten in six matches – eased past RSL at Providence Park on Saturday.
Felipe Mora, Dairon Asprilla, Jaroslaw Niezgoda and Cristhian Paredes also scored for the Timbers, who have netted in 16 consecutive matches against RSL (including play-offs) – the second longest streak against any opponent in their history, behind the 17 straight versus Dallas from August 2012 to March 2018.
The Timbers led 2-1 at half-time before putting RSL to the sword in the second period to match their six-game unbeaten streak from September-October last season.
Portland are fourth in the Western Conference, six points behind leaders Sporting Kansas City, while RSL occupy the seventh and final play-off position in the west.
Los Angeles FC are three points outside the top seven following their 2-0 defeat to San Jose Earthquakes, while Vancouver Whitecaps are also on 33 points after topping Dallas 1-0.
The Union defeated Atlanta 1-0 thanks to Kacper Przybylko's goal with less than 20 minutes remaining.
Back-to-back wins sent Philadelphia up to fourth in the Eastern Conference as Atlanta's three-game winning streak came to an end to leave them eighth in the east and outside the post-season positions.
In other results, Supporters' Shield leaders New England Revolution were 2-1 winners over Orlando City.
The Revolution extended their MLS single-season record for wins by one-goal margins to 16. Nine of New England's last 10 MLS victories have come by a one-goal margin.
It continued Orlando's misery against New England – the team have never won at the Revolution (D1 L5), the only side they have visited more than three times without recording a victory in MLS play.
DC United prevailed 4-2 against FC Cincinnati, New York Red Bulls overcame rivals New York City 1-0, defending champions Columbus Crew won 2-1 against Montreal, Houston Dynamo lost 2-0 to Minnesota United, while Colorado Rapids and Toronto played out a 0-0 draw.
Second-half strikes from Sebastian Blanco and Felipe Mora earned the Timbers the points, ending Seattle's three-game winning run and ensuring they missed the chance to extend their lead to five points.
Portland had failed to win in their past three games, with the result lifting them from 10th in the west, up to sixth.
Blanco's goal was particularly special, having torn his anterior cruciate ligament (ACL) at the same venue nearly a year ago.
Mora pounced on a poor Yeimar Gomez Andrade back pass, swooping in and setting up Blanco for a 58th-minute tap-in.
Timbers goalkeeper Steve Clark made numerous saves, including from a rocket 61st-minute Joao Paulo volley, before Mora capitalised on an error from Sounders keeper Stefan Cleveland, sealing the points with a classy lob in the fifth minute of stoppage time.
Eight goals were scored in an entertaining Texas derby as Dallas got the better of Austin 5-3 – teenager Ricardo Pepi and Jesus Ferreira both netting braces for the winners.
Dallas raced to a 4-1 lead at the break before Jader Obrian added a fifth shortly after half-time, with Austin pulling goals back via Diego Fagundez and Alexander Ring as Ferreira hit the post late in pursuit of a hat-trick.
Pepi, who turned 18 in January and last month became the youngest player in MLS history to score a hat-trick, has netted 11 times this season for Dallas.
Meanwhile, Vancouver Whitecaps continued their resurgence under interim head coach Vanni Sartini with a 4-1 rout of Real Salt Lake.
The Whitecaps piled on three goals inside 16 second-half minutes after Marcelo Silva's own goal had given them a 1-0 lead at the interval.
Cristian Dajome was dangerous down the right flank, as Brian White, Ryan Gauld and Florian Jungwirth netted before Anderson Julio's consolation for RSL.
Alejandro Pozuelo's fine run of form continued as Toronto came from behind to beat the Philadelphia Union 2-1 in Connecticut.
Sergio Santos' delicate chip had put Philadelphia ahead in the fifth minute, but Toronto fought back in the second half.
Ayo Akinola headed in a Tony Gallacher cross from the left approaching the hour-mark to bring Greg Vanney's side level.
Pozuelo scored what proved to be the winner in the 76th minute, heading in at the back post following a corner.
As Toronto won for the 10th time in their past 13 meetings with the Union, Pozuelo has been directly involved in 10 goals since the MLS regular season resumed in August, as per Opta.
Toronto joined Columbus on 31 points atop the Eastern Conference after the Crew were held to a 2-2 draw by Dallas.
LA Galaxy are bottom of the Western Conference after slumping to a 2-1 loss to the San Jose Earthquakes in the California Clasico.
The Galaxy seemed on track when Sebastian Lletget put away the opener after Javier Hernandez hit the post, and goalkeeper David Bingham saved Chris Wondolowski's 12th-minute penalty.
But Marcos Lopez drilled in a wonderful equaliser before half-time, and Andres Rios made no mistake with San Jose's second spot-kick of the game in the 82nd minute.
Orlando City continued their fine season with a 3-1 victory over the New York Red Bulls.
The club's tally of 29 points from their first 15 matches is five more than they have ever had through the same number of games in any previous campaign, according to Opta.
Gonzalo Higuain's Inter Miami fell to a 3-2 loss to New York City, while Atlanta United crushed DC United 4-0.
Montreal Impact and Chicago Fire drew 2-2, Alan Pulido scored a brace as Sporting Kansas City edged Houston Dynamo 2-1 and Minnesota United enjoyed a 2-0 victory over Cincinnati.
Western Conference leaders the Seattle Sounders beat the Vancouver Whitecaps 3-1, while the clash between the New England Revolution and Nashville finished goalless.
White scored a hat-trick as the Whitecaps moved within just one point of the seventh and final post-season spot in the Western Conference heading into the last seven matches of the regular season.
A recruit from New York Red Bulls following June's trade, White – who has scored eight goals in his past nine games – opened the scoring in the 26th minute.
White doubled the lead with a header approaching the hour mark before completing his first career hat-trick 17 minutes from the end – using his head to get on the end of Ryan Gauld's corner.
Montreal topped fellow Eastern Conference play-off hopefuls Atlanta United 2-1 courtesy of Romell Quioto's double.
Heading into the fixture, twelve of the last 15 goals conceded by Atlanta had come in the second half of their games and none of those 15 goals were shipped in the first half an hour.
Quioto scored a five-minute brace inside the opening 10 minutes of the second half to lift Montreal up to fifth in the east, while striking a blow to Atlanta's post-season chances.
Atlanta are eighth and outside the play-off spots – level on points with seventh-placed Philadelphia Union, who have played two games less.
Elsewhere, Orlando City catapulted themselves up to third in the Eastern Conference after Daryl Dike's 97th-minute goal snatched a 2-1 win over DC United, the Red Bulls edged FC Cincinnati 1-0, Austin defeated Real Salt Lake 2-1 and Dallas played out a 0-0 draw with 10-man Minnesota United.
Cadiz – making his second appearance after arriving on loan from Portuguese giants Benfica – doubled the lead with 17 minutes remaining on Tuesday.
Coming off the bench just past the hour-mark after Randall Leal opened the scoring in the 19th minute, Cadiz's long-range shot took a deflection and left Dallas goalkeeper Jimmy Maurer helpless.
Fellow substitute Daniel Rios completed the scoring in the 88th minute when weaved his way past two defenders, sending a scrambling Reto Ziegler to the ground, before firing low beyond Maurer.
The result ensured expansion franchise Nashville earned back-to-back MLS wins for the first time, per Opta.
Of Nashville's 24 points so far, 11 have been won against teams from Texas – seven versus Dallas and four against Houston Dynamo.
Nashville are eighth in the Eastern Conference, while Dallas are sixth in the west following just one win in six games.
The Revs have lost three straight matches and four of their last five, their latest defeat coming by a 5-1 scoreline versus the Philadelphia Union in midweek.
They are bottom of the Eastern Conference, already 11 points adrift of a guaranteed playoff place and five off the play-in spots, yet Porter remains positive.
"We have to be better. I still feel very good about our chances but certainly, a win on Saturday would go a long way to setting us up ahead of the Leagues Cup and the run-in," Porter said.
"I still feel very good about our chances, we've got games in hand. We should be healthier in those games.
"What I'm looking for is a result by any means possible."
Dallas, meanwhile, sit 11th in the West but are looking up after a difficult start, making it three wins from their last four matches in midweek.
After their 3-1 derby win over Austin FC, interim head coach Peter Luccin said courageous play will be key if they are to continue moving forward.
"This is FC Dallas' style, we want to play from the back. I like the ball, I think the team likes the ball, but to play from the back, we need courage to show in the right moments," he said.
"This is a thing that we'll have to improve because in the very specific and important moments, we didn't show for the ball.
"But we are working on that and it's going to take time. Right now what we can see and I think what everybody can see is that the team is ready to compete. The team is competing every single game."
PLAYERS TO WATCH
New England Revolution – Xavier Arreaga
The Revs' 5-1 defeat at Philadelphia on Wednesday was the third time they have conceded five or more goals in all competitions this season after not doing so once from 2020 to 2023.
Centre-back Arreaga will be key if they are to atone for that showing here.
FC Dallas – Petar Musa
Musa has scored in four straight MLS matches, the longest streak by a Dallas player since Paul Arriola did so in five straight in May 2022.
Musa and Arriola are the only Dallas players to score in at least four straight league matches over the last six seasons.
MATCH PREDICTION: NEW ENGLAND REVOLUTION WIN
After winning five of six matches from early June to early July, New England have lost three league games in a row. This is the Revs' fourth losing streak of three or more games this regular season.
However, they did beat Dallas in the teams' last head-to-head meeting in March 2022, having failed to win any of their previous 10 against them (one draw, nine losses) since 2012.
Dallas' recent victories, however, have all come at home, failing to win any of their last 13 road games since last October (three draws, 10 losses). Perhaps this game represents an opportunity for slumping New England.
OPTA WIN PROBABILITY
New England Revolution – 41.5%
FC Dallas – 31.8%
Draw – 26.7%
Charlotte's win moves them up to 10th in the Eastern Conference, with the visitors scoring twice in the final quarter of an hour to claim victory.
The defeat means City have only managed one point from their past four games and sit third in the east with 42 points from 25 games.
Karol Swiderski had put Charlotte ahead in the fourth minute despite goalkeeper Sean Johnson's best efforts on the line, but City levelled before the half hour mark via Maxime Chanot's 30-yard strike into the top corner.
City's Anton Tinnerholm struck the crossbar from range before Charlotte found an avenue to victory with Swiderski's clever back-heel for Brandt Bronico to restore their lead in the 77th minute.
The visitors won an injury time penalty after video review which ex-Leicester City defender Christian Fuchs coolly converted to seal all three points.
Domenico Criscito lashed in a spectacular 75th-minute equaliser to earn Toronto a 2-2 draw with New England Revolution.
Filippo Bernadeschi had put Toronto ahead with a 31st-minute spotkick, but the Revs replied with goals either side of half-time from Tom McNamara and Justin Rennicks.
But Criscito intervened when Toronto took a corner short to Michael Bradley who lobbed to the edge of the box towards the former Italy international, who rifled in a left-foot volley.
Eastern Conference leaders Philadelphia Union were beaten 1-0 by FC Dallas with US international Jesus Ferreira scoring the only goal in the 34th minute.
Paul Arriolo broke down the right flank and passed centrally for Ferreira, who showed good skill to create space inside the box and fire a low strike past Union goalkeeper Andre Blake.
New York Red Bulls reinforced their status as playoffs contenders with a 2-1 win at struggling Atlanta United while Vancouver Whitecaps defeated Colorado Rapids 2-1.
City – the reigning champions after defeating the Portland Timbers in the 2021 MLS Cup – moved one step closer to going back-to-back when a smart cutback from Gabriel Pereira presented Maximiliano Moralez with an open goal in the sixth minute.
Their lead was doubled in first-half stoppage-time as Santiago Rodriguez picked out a beautiful ball through to Heber in behind the Montreal defence, and he tucked it away stylishly with his first-time strike from just outside the six-yard box.
Talles Magno was brought off the City bench in the 58th minute, and he assumed penalty responsibilities just three minutes later, finishing calmly into the bottom-left corner to make it 3-0.
Montreal were able to salvage a consolation goal through Djordje Mihailovic in the 85th minute, but that would be all they could muster as New York booked their place in the Eastern Conference Final against the Philadelphia Union – the east's top seed.
Later on Sunday night, two first-half goals in quick succession was enough for Austin to eliminate Dallas 2-1.
Austin jumped ahead in the 26th minute when a corner bounced its way through a crowd and found Moussa Djite at the back post, and just three minutes later they led 2-0 after Sebastian Driussi capitalised on a midfield turnover and finished well on the counter.
A slick team move resulted in Dallas pulling one goal back through Alan Valasco in the 65th minute, but they were unable to find an equaliser.
Austin will play the Western Conference's top seed, LAFC, in the Western Conference Final on Sunday.
City had ended a three-game losing run with a 2-0 win at Chicago Fire 10 days before losing to Orlando City on the weekend but their poor form continued at Red Bull Arena.
Ola Kamara tapped in from point blank range to give the visitors at 24th-minute lead, but Heber side-footed in an equalizer three minutes later.
Steven Birnbaum restored United's lead with a header from a Martin Rodriguez free-kick in the 57th minute and City could not find a response with David Ochoa palming away Gedion Zelalem's 95th-minute effort.
The win is Wayne Rooney's second since taking over at United who are still last in the Eastern Conference, while it sees City slide down to fourth in the east.
Riqui Puig scored a spectacular late equalizer with a long-range curler after a give-and-go to earn LA Galaxy a 2-2 draw away to Toronto.
Douglas Costa had put the Galaxy into a 24th-minute lead before Toronto hit back with second-half goals to Jesus Jimenez and Filippo Bernardeschi before the Spaniard's 89th-minute strike.
Riqui Puig was making only his third appearance for the Galaxy following his August move from Barcelona.
The result dents star-studded Toronto's playoffs aspirations, leaving them 10th in the east, while the Galaxy are eighth in the west.
Philadelphia Union became the second team behind LAFC to book their postseason berth with a 4-1 home win over Atlanta United.
Julian Carranza, Mikael Uhre, Daniel Gazdag and Nathan Harriel were all among the goals for Union who are eight points clear in the east.
New York Red Bulls moved up to third in the east with a 1-0 win at second-placed Montreal with Lewis Morgan hitting the winner in the 43rd minute.
LAFC suffered a shock 2-1 loss to lowly Houston Dynamo, who condemning the Western Conference leaders to their third straight defeat.
Inter Miami slumped to back-to-back losses with a 1-0 defeat at Columbus Crew, while New England's winless run extended to four games after a goalless draw with struggling Chicago Fire who snapped a three-game losing run.
Hany Mukhtar netted a hat-trick as Nashville beat Colorado Rapids 4-1, while Orlando City came from two goals down to defeat Seattle Sounders 3-2.
Real Salt Lake proved too good for Minnesota United 3-0 and Portland Timbers moved into the west's top seven with a narrow win against second-placed Austin 2-1.
City had ended a three-game losing run with a 2-0 win at Chicago Fire 10 days before losing to Orlando City on the weekend but their poor form continued at Red Bull Arena.
Ola Kamara tapped in from point blank range to give the visitors at 24th-minute lead, but Heber side-footed in an equalizer three minutes later.
Steven Birnbaum restored United's lead with a header from a Martin Rodriguez free-kick in the 57th minute and City could not find a response with David Ochoa palming away Gedion Zelalem's 95th-minute effort.
The win is Wayne Rooney's second since taking over at United who are still last in the Eastern Conference, while it sees City slide down to fourth in the east.
Riqui Puig scored a spectacular late equalizer with a long-range curler after a give-and-go to earn LA Galaxy a 2-2 draw away to Toronto.
Douglas Costa had put the Galaxy into a 24th-minute lead before Toronto hit back with second-half goals to Jesus Jimenez and Filippo Bernardeschi before the Spaniard's 89th-minute strike.
Riqui Puig was making only his third appearance for the Galaxy following his August move from Barcelona.
The result dents star-studded Toronto's playoffs aspirations, leaving them 10th in the east, while the Galaxy are eighth in the west.
Philadelphia Union became the second team behind LAFC to book their postseason berth with a 4-1 home win over Atlanta United.
Julian Carranza, Mikael Uhre, Daniel Gazdag and Nathan Harriel were all among the goals for Union who are eight points clear in the east.
New York Red Bulls moved up to third in the east with a 1-0 win at second-placed Montreal with Lewis Morgan hitting the winner in the 43rd minute.
LAFC suffered a shock 2-1 loss to lowly Houston Dynamo, who condemning the Western Conference leaders to their third straight defeat.
Inter Miami slumped to back-to-back losses with a 1-0 defeat at Columbus Crew, while New England's winless run extended to four games after a goalless draw with struggling Chicago Fire who snapped a three-game losing run.
Hany Mukhtar netted a hat-trick as Nashville beat Colorado Rapids 4-1, while Orlando City came from two goals down to defeat Seattle Sounders 3-2.
Real Salt Lake proved too good for Minnesota United 3-0 and Portland Timbers moved into the west's top seven with a narrow win against second-placed Austin 2-1.
City were in control throughout, creating 16 shots in the first half compared to just four for Miami, but they went into halftime tied at 0-0 after hitting the woodwork three times.
In one instance, a turnover from Miami goalkeeper Drake Callender handed City's Heber a golden opportunity to break the deadlock, but his chip was cleared off the line into the crossbar, with the rebound then being hacked off the post by a second defender.
City's dominance was rewarded in the second half, with Santiago Rodriguez brilliantly working his way into the Miami penalty box before dishing it off for Gabriel Pereira to finish in the 63rd minute, before Rodriguez also set up the second goal six minutes later with a clever backheel to Maximiliano Moralez.
Heber completed the rout in stoppage time to end the career of Miami's iconic striker Gonzalo Higuain, who was playing in his final season, with City now set to take on Montreal in the Eastern Conference semi-finals.
Later in the day, FC Dallas needed a penalty shoot-out to advance past Minnesota in the Western Conference.
Emanuel Reynoso's goal for Minnesota in the 53rd minute was canceled out by a 64th-minute strike from Facundo Quignon, and after 30 minutes of extra time, it all came down to penalties.
It was Minnesota's captain Wil Trapp who failed to come through with his side's second penalty, with his tame effort into the bottom-left corner being saved by Dallas' Maarten Paes, before Alan Velasco finished things in style with a cheeky panenka.
A day after the MLS is Back Tournament was announced, the league held a draw for the group stage on Thursday, placing the 26 teams into six groups.
Sixteen teams will then progress to the knockout stage, which will begin on July 25 ahead of an August 11 final.
Aside from the opening match, the rest of the tournament schedule has yet to be announced.
The groups for the MLS is Back Tournament:
Group A (Eastern Conference): Orlando City, Inter Miami, New York City, Philadelphia Union, Chicago Fire, Nashville SC.
Group B (Western Conference): Seattle Sounders, Dallas, Vancouver Whitecaps, San Jose Earthquakes.
Group C (Eastern Conference): Toronto, New England Revolution, Montreal Impact, DC United.
Group D (Western Conference): Real Salt Lake, Sporting Kansas City, Colorado Rapids, Minnesota United.
Group E (Eastern Conference): Atlanta United, FC Cincinnati, New York Red Bulls, Columbus Crew.
Group F (Western Conference): Los Angeles FC, LA Galaxy, Houston Dynamo, Portland Timbers.
