Defending MLS champions Seattle Sounders booked their spot in the Western Conference semi-finals after accounting for Los Angeles FC 3-1.

Seattle booked their spot in the second round of the play-offs thanks to goals from Jordan Morris, Nico Lodeiro and Raul Ruidiaz on Tuesday, earning a home date with Dallas.

Morris, Lodeiro and Ruidiaz all scored in the same MLS match for the fourth time, more than any other trio of team-mates since the start of the 2018 season, per Opta.

Lodeiro opened the scoring in the 18th minute – Morris teeing up the Uruguayan for a first-time shot past LAFC goalkeeper Pablo Sisniega.

LAFC's star captain Carlos Vela had a penalty saved three minutes later as Sounders goalkeeper Stefan Frei stopped a non-shoot-out spot-kick for the first time since April 2016, after allowing goals on the previous 18 on-target penalties he had faced.

After Morris and Lodeiro hit the woodwork in quick succession, Ruidiaz doubled the lead in the 66th minute before Eduard Atuesta reduced the deficit 11 minutes later.

Morris, though, restored Seattle's two-goal advantage within three minutes as the Sounders moved through to the next round.

Meanwhile, expansion franchise Nashville stunned Toronto 1-0 after extra time to earn an Eastern Conference semi-finals berth.

Daniel Rios' 108th-minute goal settled the contest in Connecticut, where seventh seeds Nashville became the third team in MLS history to win each of their first two play-off matches.

Rios' winner was also the first Toronto has ever conceded in extra time of a MLS play-off clash.

Nashville will now face Columbus Crew for a place in the Conference finals.

In the day's other fixture, New England Revolution shocked Eastern Conference top seeds Philadelphia Union 2-0.

First-half goals from Adam Buksa and Tajon Buchanan set the tone for the Revolution, who are the first team to score multiple goals in an away match against the Union all season.

Next up for Bruce Arena's Revolution are Orlando City.