CLEVELAND — Midway through the second quarter of Tuesday night's debacle, LeBron James threw down a rim-rattling one-handed dunk, then tilted his head back in a long, primal scream.

He might as well have yelled: Welcome to the Eastern Conference finals, Toronto.

The four-time NBA MVP scored 24 points on near perfect shooting, while Kyrie Irving had 27 as the Cavaliers throttled the Raptors 115-84 in Game 1 on Tuesday — Toronto's first conference finals appearance in franchise history.

"I thought they were the fresher team, the quicker team tonight. (But) it's one game," said Raptors coach Dwane Casey. "This series is not over by any means. We have another game on another night.

"The score is embarrassing, but again, it's just one game."

James punished the weary Raptors on 11-for-13 shooting, scoring on his first nine shots, and looking for most of the night like a man playing against boys.

DeMar DeRozan had 18 points, but the rest of the Raptors could do little against a Cavaliers team that went into the night after a nine-day break. Bismack Biyombo had 12 points, while James Johnson finished with 10.

"We're surely not going to make no excuses, but they've been off their feet, we've been battling for the last couple of weeks, and they came up with that. . . quick first step," DeRozan said. "We didn't meet it like we wanted to."

The Raptors hung in with the home team through the opening quarter, but almost as if they'd been toying with Toronto, the Cavaliers then thrust a foot on the throat of the Raptors and held it there until the final, merciful, buzzer.

When James blew past DeMarre Carroll for his massive windmill dunk that had the 20,562 fans roaring, it capped a 20-2 Cavaliers run and it was all but game over for Toronto already. Cleveland's 22-point lead in the second quarter became a whopping 28 points by the end of the third, as the Cavs took a 95-67 advantage into the fourth.

Casey waved the virtual white flag with 10 minutes to play, pulling his starters for seldom-used Delon Wright and Jason Thompson.

When Terrence Ross went up for what should have been an easy dunk with six minutes left to play, the ball bounced out, an apt metaphor on an ugly night. With three minutes to play, fans erupted into chants of "U-S-A!"

Cleveland held Kyle Lowry, who scored 35 points in Toronto's Game 7 win over Miami, to just eight. Neither Lowry nor DeRozan went to the free throw even once on the night.

"Just us being more aggressive," DeRozan said. "We've got to come out the gate with that mindset, being aggressive like we usually do, and I think we didn't try to do that until later on in the game."

The Cavs outrebounded Toronto 45-23, and while they'd been burning opponents from three-point range in these playoffs, they instead attacked from close range, clobbering Toronto 56-36 in the paint.

"It's our preparation," James said of Cleveland's unblemished post-season. "We understand the moment and guys are rising to that."

The Cavaliers' straight-line drives to the net were "demoralizing," a somber Casey said after the blowout.

"Very demoralizing. You want to take away one thing (three-point shooting), but you don't want to open up a whole can of worms to give them layups, and that's what we've got to be disciplined with."

The 31-point win is the most lopsided in Cleveland's post-season history.

Game 2 is Thursday in Cleveland, then the series shifts to the Air Canada Centre for Game 3 on Saturday and Game 4 on Monday.

The Raptors had a 2-1 edge over the Cavs in the regular-season series. But Cleveland has been red-hot in the post-season, making quick work of Detroit and Atlanta in the first two rounds, and relegating the Raptors to the under-dog role.

The Cavaliers' two sweeps allowed them a nine-day break, while the battle-wearing Raptors arrived in Cleveland to play just two days after finally knocking off Miami in Game 7 of the conference semifinals. They also needed seven games to dispatch Indiana in the first round.

"We didn't rest," James shot back, when asked about the long break. "We just didn't have a game. Coach gave us one day off, other than that we were in the gym. So we didn't rest. We just didn't have a game in front of the cameras."

Quicken Loans Arena was awash in gold, with small pockets of Raptors fans. Montreal Canadiens star P.K. Subban had a front row seat, as did UFC heavyweight champion Stipe Miocic.

Casey had wanted his team to come out "guns a-blazing," and they did with an early 7-0 lead. Still, DeRozan's 12 points in the first quarter weren't enough against the Cavs, who led 33-28 going into the second.

The Cavs promptly found another gear and an Iman Shumpert dunk had them up by 19 just five minutes into the frame. Cleveland went into halftime up 66-44. The Raptors' deficit tied for the worst in their playoff history.