Nick Nurse after the Raptors' Game loss says the team needs to work harder and gain confidence before Game 2 on Friday. (0:44)

MILWAUKEE -- As the final seconds of the third quarter of Game 1 of the Eastern Conference finals bled away, Toronto Raptors forward Pascal Siakam brought the ball upcourt. At the last moment, and still a couple of steps behind the 3-point line, he rose up for a shot over the outstretched arm of Milwaukee Bucks star Giannis Antetokounmpo, and the ball softly dropped through the net as the buzzer sounded.

The basket gave the Raptors an 83-76 lead after three quarters and seemingly had them poised to steal home-court advantage from the top-seeded Bucks in this series. Instead, it turned out to be the final field goal that any Raptor not named Kyle Lowry would make Wednesday night.

Rather than take an early lead in the series, the Raptors instead saw the Bucks outscore them 32-17 in the final quarter, as Milwaukee emerged with a 108-100 victory in front of a sellout crowd here at Fiserv Forum.

"Pretty frustrating," Lowry said. "Fourth quarter killed us. ... They outplayed us in the fourth quarter. They got a little bit more aggressive. They made some big shots, made some big plays.

"It sucks when you lose like that. But we had a chance. We've got to learn from it, make an adjustment. [We have to] stay even-keeled ... not too high, not too low. Just look at the film and get better."

The fourth-quarter film will highlight an ugly picture. Lowry was fantastic, going 5-for-7 from the floor and scoring 14 of his 30 points in the final 12 minutes alone. The rest of the Raptors, though, were awful. Toronto's other seven players who saw time in the fourth combined to go 0-for-15 from the floor, including 0-for-7 from 3-point range, with the only other points coming on free throws by Kawhi Leonard (two) and Siakam (one).

"Couple key turnovers," Leonard said after finishing with 31 points but going 0-for-3 and only scoring those two points in the fourth. "Missed some easy layups, some wide-open 3s. And we didn't play too well on defense. ... They ended up scoring their highest-quarter points in the fourth quarter. [That] pretty much sums it up."

Toronto saw that initial lead entering the fourth instantly evaporate in the opening two minutes while Leonard was on the bench. The Raptors had three open looks -- a Norman Powell layup, a Fred VanVleet midrange jumper from the top of the key and then a VanVleet 3-pointer from the wing -- but none of them went in.

On the other end, Milwaukee -- which went a combined 6-for-34 from 3-point range through the first three quarters -- immediately got two straight 3s from Brook Lopez (who finished with a team-high 29 points to go along with 11 rebounds and four blocks) and a pair of free throws from Nikola Mirotic to take its first lead since early in the first quarter.

And while the teams went back and forth over the final few minutes -- thanks in large part to Lowry's heroics -- after Leonard drained two free throws to make it 100-98 with 3:31 remaining, the Bucks scored the final 10 points to seal the victory. Toronto missed its final eight shots over that span, including five 3-pointers.

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Milwaukee controlled the paint throughout the game, winning points in the paint (44-26), second-chance points (24-13) and fast-break points (25-15), while also turning Toronto's 12 turnovers into 20 points. Meanwhile, the Raptors not named Leonard or Lowry finished a combined 14-for-51 from the floor.

"It's gonna be an interesting series," said Siakam, who finished 6-for-20 from the field for 15 points, "and we know we had a chance to win tonight. We felt like we could've gotten this game, but obviously, we didn't. And credit to them, they came back and took the game from us.

"But it's a long series, and we've got to bounce back and be better next game if we want to get out of here with a win."

Perhaps some fatigue set in after Toronto's survival of a grueling seven-game series with the Philadelphia 76ers in the Eastern Conference semifinals, a series the Raptors won thanks to Leonard's incredible buzzer-beater Sunday evening. The Bucks, on the other hand, finished off the Boston Celtics in five games and had a week to rest and prepare at home for this game, and Milwaukee certainly looked like the fresher team down the stretch.

From Toronto's standpoint, though, the why of how this game played out the way it did ultimately was irrelevant. A chance to take control of this series right off the bat had been wasted. Now the Raptors have no choice but to try to find a way to put themselves in a similar position when these teams meet again here Friday night in Game 2 of this best-of-seven affair.

"Each one of these games is critical," Raptors coach Nick Nurse said. "I thought we played tough tonight, a tough brand of basketball, for the most part.

"We gave ourselves a chance to win a game on the road in the Eastern Conference finals. It didn't turn out, and we put in a lot of work, but you're going to file that one away and put in more work the next time.

"We gotta get some rest here tonight, focus in on our film, figure out some adjustments, build up some confidence," Nurse added. "But then again, once it gets ready to go up for Game 2, we have to be tough."