TORONTO -- The Cleveland Cavaliers remain undefeated in their first eight playoff games this season.

That does not mean it has been easy, even though they were able to complete a four-game sweep of their Eastern Conference semifinal series on Sunday afternoon with a 109-102 victory over the Toronto Raptors after giving up the lead in the fourth quarter.

"We understand it's never easy especially in a close-out game," said Cavaliers guard Kyrie Irving, who scored 11 of his 27 points in the fourth quarter and added nine assists. "There's desperation at their end and desperation at our end."

LeBron James scored 35 points, grabbed nine rebounds and had six assists to lead the Cavaliers, who won the NBA championship last season and will play either the Boston Celtics or Washington Wizards in the Eastern Conference finals.

"Winning close-out games is always tough," Cleveland coach Tyronn Lue said. "Give credit to (Raptors coach Dwane) Casey, he had them ready to play, they came out and competed. They made threes today, it was tough on us."

The Raptors were playing without point guard Kyle Lowry, who sustained a sprained left ankle in Game 2 on Wednesday. He was in uniform for Game 3 but did not play and was scratched from Game 4.

"They have good players, even without Kyle," Lue said.

Casey said, "It's tough because we know we can play better than we did in the first two games, and we didn't. Today, I thought the players laid it on the line. I thought the guys played with grit, toughness, togetherness. ...

"(The Cavaliers) present so many problems offensively, they have so many weapons. ... The way they were making shots, and they were well-guarded, you're going to have to score 117-118 points a night to beat them."

Cleveland had a 12-point lead after the first half and entered the fourth quarter ahead by five.

The Raptors took a 93-92 lead with 6:38 to play when Serge Ibaka made a free throw to complete a three-point play.

Irving put the Cavaliers back on top with a 3-pointer and with 5:34 to go and made two free throws to make it a four-point lead.

Irving's layup with four minutes remaining had Cleveland ahead by eight points.

"In that fourth quarter, I just went to (isolations) for Kyrie," Lue said.

"We needed that spark," said James, who hit a 3-pointer with just under three minutes left to put the Cavaliers ahead by 11.

"They went to him on isos," Raptors point guard Cory Joseph said. "I tried my best ... but he made some tough shots."

"A lot of the offense was on LeBron's shoulders," said Irving, who was willing to share the load.

James had nine points in the fourth quarter.

Kyle Korver added 18 points, including 4 of 6 on 3-point attempts, for the Cavaliers off the bench, and Channing Frye contributed 10 points.

Ibaka scored 23 points for the Raptors, DeMar DeRozan had 22 points and eight assists, Joseph scored 20 points and added 12 assists, P.J. Tucker had 14 points and 12 rebounds, and Norman Powell scored 10 points.

"You have to give them credit, they are a heck of a 3-point-shooting team," DeRozan said. "They get hot, one of the best shooters in the league in Kyle Korver. They do a great job of getting him going and it showed tonight.

"They're a hell of a team for a reason. They have one of the greatest players of all time. It's something that we great experience with playing these guys two years in row (in the playoffs, including the Eastern Conference finals last year) and we just have to figure it out. ... It's going to be a long summer."

Toronto led by as many as 11 points in the first quarter that ended tied at 28. DeRozan left the game briefly with 8:07 to play in the second quarter after he was inadvertently kicked in the midsection while guarding Iman Shumpert.

The Cavaliers opened a 14-point lead on Korver's 3-pointer late in the first half.

Cleveland led 61-49 at the intermission with James and Korver leading the scoring with 16 points apiece. Korver, who did not play in the first quarter, was 6 of 8 in the second quarter, including his four 3-pointers.

The Cavaliers got their lead up to 16 points in the third quarter before the Raptors chipped away to reduce the lead to seven points on Ibaka's 3-pointer from the corner with 4:44 to play.

Tucker closed out the scoring in the third quarter with a 3-pointer from the corner to cut Cleveland's lead to 85-80.

Tucker opened the scoring in the fourth quarter with a 3-pointer to slice the deficit to two points. The Raptors trimmed the lead to one point early in the fourth on a 3-point shot by Fred VanVleet but James answered with a 3-pointer.

NOTES: Toronto activated C Lucas Nogueira for Game 4 after PG Kyle Lowry (sprained left ankle) was scratched from the lineup. PG Cory Joseph started at point guard for the Raptors with Lowry out. ... There were no points in the first 2:19 of the game before Cleveland F LeBron James scored on a dunk off a fastbreak. ... The Raptors shot 50 percent from the field in the first half but committed 11 turnovers leading to 17 Cleveland points. Cleveland's five first-half turnovers led to only two points.