Toronto Raptors coach Nick Nurse sat down for his postgame news conference and started looking for answers.

For only the second time since the NBA season restarted, his Raptors dropped a game. It just so happened to occur against the same team -- the Boston Celtics. Boston dominated Toronto in all facets Sunday in a 112-94 win in Game 1 of their Eastern Conference semifinal series in Lake Buena Vista, Florida.

The Raptors were seemingly in trouble from the start. On the first play of the game, guard Fred VanVleet missed a layup. Next time down there was a missed 3-pointer from Kyle Lowry. Then two more missed shots and two turnovers followed.

By the time Toronto scored, nearly three minutes had run off the clock. Throughout the entire first quarter -- and really throughout the game -- Boston kept the Raptors from finding any sort of rhythm offensively. And Nurse noticed.

"Obviously we're not ourselves," Nurse said. "I think more, we have to play a lot better. I think especially at the offensive end. We really just weren't very good. We didn't make many shots. We didn't play with great composure. We didn't execute very well. It was a rough one today on a lot of fronts. I think that the actual X's and O's and the tactical part, we'll need to do better. But it wasn't a very good rhythm on the day for us."

It certainly didn't help the Raptors that they were whistled for 11 fouls in the first quarter, including three on Pascal Siakam -- the third of which Nurse unsuccessfully challenged. But Nurse wasn't about to let the blame fall on the referees.

"It was tough but it was all part of a bad rhythm," Nurse said. "We didn't play nearly well enough or hard enough or good enough or fast enough or tough enough to win today, because we got our butts kicked."

Siakam, the Raptors' All-Star forward, finished with 13 points on 5-of-16 shooting with just three rebounds. Since play has started in Florida, Siakam has struggled to find a rhythm of his own.

In the 12 games since the restart, Siakam is averaging 17.8 points while shooting 39.6% from the field and 31.9% from deep. In 53 games prior to the NBA's hiatus in March, he was averaging 23.6 points on 45.9% shooting while making 35.9% from 3-point range.

Nurse said the team will continue to try to get Siakam going in all phases of the game moving forward.

"I think we'll always look at trying to get him involved in about all areas as opposed to as a player or a jump-shooter or a handler in the screen-and-roll or center in the screen-and-roll," Nurse said. "I think we gotta mix it up and vary it, even some isolations on top, isos on the side. Hopefully get him involved in the transition game a little bit as well."

Siakam was clearly slowed down by the three first-quarter fouls, but said he felt he was getting the shots he wanted throughout the game -- he just needed to finish those attempts.

Siakam also wasn't interested in looking at this past week's events -- including players deciding whether or not to continue the playoffs and delaying Game 1 of this series from Thursday to Sunday -- as a crutch for the Raptors' poor performance.

"You can't make excuses, man; it's basketball. You go out there; you play," Siakam said. "This is something that we love to do, been doing it for a while. And obviously it's tough, and you don't want to minimize the things that's going on. But once we step on the floor, it's time to play, and we gotta be able to do our best and play and do everything to be our best. So we can't really have those things as excuses.

"It was an emotional week, and a lot of things happened, and a lot of debate between staying and leaving. But for me, I was like, 'If we're here, we're here.' There's no more -- we gotta be here and we just gotta play, and we can't use that as an excuse."

One thing that works in Toronto's favor is its history of battling back from early stumbles.

Last year, Toronto lost Game 1 in the first round, then went down 2-1 in the conference semifinals and 2-0 in the conference finals. Only one of those series went to a seventh game as the Raptors rolled to the Finals, where they lost Games 2 and 5 before coming back to win the NBA title in six games.

"I think we learn from games," Siakam said. "Obviously it was one of those games, and I didn't play well, and we didn't really have a rhythm offensively. I don't think our defense was bad; we made some mistakes and stuff. But we just try to go back and watch the film, and just try to be better."

One thing that will have to change, according to Nurse, is the Raptors' transition offense.

In the regular season and first round, Toronto averaged a league-high 19.2 transition possessions per game, according to Second Spectrum data, and averaged 1.3 points per possession on those plays, the seventh-best mark in the NBA.

Against Boston on Sunday, Toronto had 19 transition possessions but scored only 19 points. Only once since the restart had the Raptors registered a lower points-per-possession average (0.93 against Miami on Aug. 3).

But in order to get that going, the Raptors have to get stops on the defensive end.

"It's almost impossible to score in transition when the ball goes through the net and you have to take it out," Nurse said. "I thought we got a lot of defensive rebounds and we got a lot of turnovers that we didn't turn into much. Again, a little bit of just the energy of the game. That was just another factor. The energy of the game wasn't very good for us."