Boston Celtics coach Ime Udoka believes his side responded well to being "punked" by the Miami Heat, claiming a 127-102 win in Game 2 of their playoff series on Thursday.

A 39-14 third quarter in the Heat's favour effectively decided Game 1 as the Celtics collapsed on the road, but bounced back, cutting down turnovers and putting four quarters together to split the first two games in Miami.

Marcus Smart and Al Horford's returns to the line-up were critical for the Celtics as they claimed home-court advantage against the Eastern Conference's first seed, but it was a collective effort with 28 assists off 43 made field goals.

Udoka praised his side's mental toughness in responding against a side that came at them in the opening game of the series.

"I think we were upset with how that third quarter went, specifically how we got out-toughed," Udoka said post-match. "Wasn't a lot of schemes or defensive or offensive changes, they just came at us and kind of punked us in that third quarter.

"We looked the other three quarters and how well we had done in winning those quarters, and knew if we just matched their physicality, we could be better. It kind of reminded us of Milwaukee a little bit – the first game – and didn't want to get caught off-guard again.

"I think our guys have bounced back really well all year, especially the second half of the year. Haven't lost two games in a row in a while, and obviously having Marcus and Al back gave us a little boost as well."

Smart was an important figure in his return from a foot injury, filling the stats sheet and finishing with 24 points, 12 assists, nine rebounds and three steals.

Horford provided a little bit of everything meanwhile, ending the game with 10 points, three assists and rebounds as well as a steal and a block.

Udoka commended the returning duo, allowing the team to capitalise on positive aspects from the first game.

"It was great to have the vets back, obviously," he said. "A calming presence there. We didn't get off to our best start, we were a little slow to start but we fought right back into it.

"After, I guess, the first five or six minutes we held them down scoring-wise, but it was a good overall effort. I felt we didn't play as poorly as the last game showed.

"Like I said, we won three quarters and had a very bad third quarter, it was hard to overcome but we saw a lot of positives and areas we could attack."

Boston Celtics forward Jayson Tatum has taken the blame for his turnovers in the Miami Heat's game-changing 22-2 third-quarter run in Tuesday's Conference Finals Game 1 defeat.

The Celtics led 62-54 at half-time but were blown away by the Heat in a staggering 39-14 third quarter where Boston gave up eight turnovers, including six from Tatum.

Boston were not helped by poor shooting offensively, with their two-of-15 (13 per cent) from the field in the third being their worst in any quarter over the last four seasons.

"They were down at half-time and came out and played hard in the third quarter," Tatum told reporters after the game.

"It's on me, I had six turnovers. I've got to take care of the ball better, especially in those situations when they're going on runs like that."

Celtics head coach Ime Udoka said his side lost their composure during the third quarter, with Jimmy Butler starring for the Heat at both ends.

Butler finished the game with 41 points, including 27 in the second half, while he also had four steals and three blocks.

"They looked like they came out in the second half and wanted to up their physicality and aggression at both ends," Udoka said.

"I don’t think we obviously responded well on either end of the floor. We had eight of our 16 turnovers in that quarter.

"It flipped very quickly. We lost our composure."

The win gives the Heat a 1-0 series lead but Udoka was eager to point out that the Celtics won three of the four quarters, offering hope moving forward.

"We won three quarters other than that but obviously that one is going to stand out, 39-14 on two-of-15 is tough to overcome," he said.

"We won the transition battle, won the second-chance points battle we won the points in the paint, really had one poor quarter that hurt us.

"It was strictly from a physically standpoint. It wasn’t anything different that they did. At least we bounced back in the fourth."

Jaylen Brown said he and his Boston Celtics team-mates wanted to play "like our season was on the line" after a 109-86 win in Game 2 of their Eastern Conference semi-final against the Milwaukee Bucks.

Brown only shot four-of-13 for 12 points in the Celtics' Game 1 defeat, but followed up by scoring 30 points, with six assists and five rebounds as Boston levelled the series at 1-1 at TD Garden.

The 25-year-old also sank a playoff career-high six shots from beyond the arc and stated after the victory just how much the Celtics had wanted to square things up.

"We knew we had to come out and play like our season was on the line and we did that," Brown said.

"It's the playoffs. Survival of the fittest. Every game counts."

As well as Brown's performance, Jayson Tatum also stepped it up as he shot 29 points, with eight assists and three rebounds.

Boston coach Ime Udoka pointed to what his team had learned in their Game 1 defeat, namely not to get "outmuscled", and just as they were dominated for large periods on Sunday, they followed up with a physical performance of their own on Tuesday.

"We adjusted well," Udoka said. "We learned some things from Game 1 and felt like we knew we didn't react accordingly to the way that we're playing.

"Two big teams but we haven't been outmuscled like that all year. I think our guys took pride in that, took that to heart and we knew we would come out with the right effort tonight."

His opposite number, Bucks coach Mike Budenholzer, acknowledged the game-plan from the Celtics had worked, particularly on star player Giannis Antetokounmpo, who still finished with 28 points, with nine rebounds and seven assists.

"The guys on him, they're solid, good, good defenders and then quite a bit of help," Budenholzer said. "That's where he's just got to see and feel it. Do we kick it and get more threes? Or he's got to finish against one-on-one defense. So, I think it's a little bit of both.

"But Giannis, he always figures things out."

Boston Celtics coach Ime Udoka remains upbeat despite his side losing home court advantage on Sunday, with the Milwaukee Bucks' 101-89 win in Game 1.

Those expecting a defensive slugfest were not disappointed, with both teams managing to restrict the other's offensive sets.

While the Bucks shot a low 41.1 per cent from the floor, the Celtics were almost spectacularly poor on the offensive end, shooting 33.3 per cent (28-of-84) and committing 18 turnovers.

Udoka tried to take the positives out of the ultimate negative, saying his side can only improve as the series progresses.

"Offensively, not the best night," Udoka said post-game. "I felt we guarded them well enough, holding them to one-on-one but to have 89 points and a lack of penetration and paint touches is alarming.

“To lose a 12-point game when we shot so poorly bodes well for us. In a way it’s good to get this dud out of the way offensively.”

In their 4-0 sweep over the Brooklyn Nets in the previous series, the Celtics averaged 34.5 three-point attempts per game.

To underline their inability to penetrate, Boston put up 50 from beyond the arc in Game 1 against Milwaukee, connecting on 18.

Jaylen Brown's three-of-nine from the perimeter to go with seven turnovers for the game was particularly microcosmic, and Udoka believes his side need to make better decisions in their offensive sets.

"As we know, that's what they want to do – protect the paint and make you shoot threes," he said. "We had some open ones, but we played in a crowd too much. That obviously shows in the amount of turnovers – 27 points off 18 turnovers.

"For the most part, I don't think our decision-making was great, whether it was a drop-off or kick-out for threes, but we need multiple [outlets] for penetration, multiple paint touches and they did a good job."

There will be plenty to play for when the Boston Celtics arrive at Fiserv Forum to take on the Milwaukee Bucks on Thursday.

Heading into the game, the Celtics (50-30) occupy the Eastern Conference two seed, while the Bucks (49-30) are a half-game back in third, holding the tie-breaker over the Philadelphia 76ers (49-30) in fourth.

Since the All-Star break, no team has a better winning percentage than the Celtics (16-4), while Milwaukee are fifth over that period (13-6); but while the reigning champion Bucks find their feet, Boston have gone to a new level.

For the season, the Celtics are number one in defensive efficiency, as new head coach Ime Udoka's switching system has maximised the physical gifts of defensive stalwarts Marcus Smart and Robert Williams III.

At this point, Boston's defense is a given, but post-All-Star break, they have also had the number one offense in the league, and are putting a gap on the rest of the field. Over that time period, the closest team to Boston's 122.2 points per 100 possessions have been the Minnesota Timberwolves, 2.7 points per 100 possessions behind at 119.5.

For context, that 2.7-point gap is greater than the 2.6-point margin between the Timberwolves and the 11th-placed 76ers (116.9) for the same period, and Boston's 12.9 net-rating since All-Star weekend is a number generally reserved for some of the greatest regular season teams in league history.

However, the team right behind the Timberwolves on the list, in third place, are the Bucks, and it is no hot streak as they boast the fifth-best offensive efficiency over the whole year.

These teams are both serious contenders to represent the Eastern Conference in the NBA Finals – but they go about it in very different ways.

Primarily, that has a lot to do with the Celtics' switching defensive system.

The Celtics 'switch' screens – meaning instead of fighting over or under the screening player to recover back to your assignment, the player guarding the screener takes on the assignment of guarding the ball-handler, while the ball-handler's defender takes responsibility for the screener and his next movements.

The Bucks, on the other hand, play 'drop coverage', which means their on-ball defender tries to force the ball-handler on a predictable path around the screen, while the screener's defender peels off into a help position, with the aim of forcing the ball-handler to pull up for a mid-range shot with their defender contesting from behind.

Both systems are formed on sound logic. In switching schemes, the idea is to eliminate as much dribble penetration as possible by keeping the ball-handler in front on the perimeter, while trusting the smaller guard to be able to deny the screener an easy catch in the paint.

Drop coverage, on the other hand, forces teams to consistently attempt mid-range jump shots, which are statistically the least valuable shot in the game.

In theory, Boston's switching defense should perform well against Giannis Antetokounmpo, as the Bucks' two-time MVP thrives at attacking the rim, while Milwaukee should be able to bait Jayson Tatum and Jaylen Brown into mid-range jump shots that can go cold for extended stretches.

But the numbers show it may not be that simple.

Boston allow the second-fewest amount of points in the paint per game, and while Antetokounmpo lives at the rim, the Bucks actually come in last in the league with their percentage of points scored in the paint.

While that may indicate that the Celtics' defense is playing right into how the Bucks like to play, Boston also allow the second-lowest three-point percentage in the league.

It poses an interesting question about Boston – is their defense truly so good that teams can not score inside the key or from long range, or is their defense the top-ranked in the league because their opponents just keep missing threes?

Opposing three-point percentage can be a messy stat due to general shooting luck, and Boston allow opponents to get up a league-average amount of attempts, so if they are due for some regression to the mean, it means they are due to be on the wrong end of some hot shooting nights.

Boston's defense also allows the lowest amount of opposition assists per game, but Milwaukee are third-last in assist percentage, so how much are the Bucks actually trying to do the things the Celtics are built to stop?

Milwaukee play at the fifth-highest pace in the league, while Boston play at the fifth-lowest – all signs point to the fact that something has to give, and whoever can play the game at their tempo may just hold the keys.

PIVOTAL PERFORMERS

Boston Celtics – Marcus Smart

Marcus Smart is not the best scorer on the Celtics, or the best ball-handler, but he excels in the areas that have made this Boston team great during the second half of this season.

He is the bookmakers' favourite to win Defensive Player of the Year due to his ability to switch off of point guards and bang bodies down low against the bigs, unlocking the true upside of a switching system as post players regularly fail to take advantage of their significant height advantage.

The Bucks are a big team, so for the Celtics defense to rise to the occasion once again against a true contender, Smart will need to hang with Jrue Holiday on the perimeter, as well as keep Antetokounmpo out of the lane.

Milwaukee Bucks – Brook Lopez

Antetokounmpo is Milwaukee's best and most valuable player. However, the centrepiece of the Bucks' drop coverage is Brook Lopez.

Lopez will be the biggest player, with the longest arms, for either team, and Milwaukee's entire defensive scheme will revolve around forcing players to take and make shots over his outstretched arms.

He also has the size, and the underrated post game, to make life miserable for whichever undersized guard gets caught in screening actions and needs to switch onto the seven-footer.

Smart will be able to hold up if he establishes good early position, but if the Bucks can get Derrick White or Payton Pritchard involved in the switch, it could be a long night inside for Boston's defense.

KEY BATTLES – Who can get the most 'easy' points?

In a game that will likely resemble a playoff atmosphere, the winning team may simply be the side who make life easiest on themselves.

Fast-break points and free throws limit the amount of possessions a team needs to grind their way through a set half-court defense, and provide the easiest avenues to uncontested points.

Milwaukee rank as the eighth-best team at getting to the free-throw line, and fourth-best at denying their opposition free throws, while Boston are 21st at getting to the line.

As mentioned, Boston like to play at a methodical pace, ranking 20th in fast-break points, while Milwaukee have the fifth-best transition defense in the league.

HEAD-TO-HEAD

These two sides have met three times this season – all before the All-Star break.

Boston won the first two home fixtures – including an overtime win where Dennis Schroeder scored a game-high 38 points, before being traded to the Houston Rockets – while Milwaukee won the last meeting, and the only one at Fiserv Forum, 117-113.