Turns out, Miami didn't even need Wade, who was sidelined by a sore knee that held him to just four points on 1-of-12 shooting in Game 3. Wade was a game-time decision Sunday for Game 4, which the Heat still won 88-77 over the Bucks.
Once again, veteran Ray Allen provided enough offense, hitting a pair of 3-pointers in the fourth quarter that had turned a two-point contest into another double-digit runaway for the defending world champions.
Allen finished with 16 points, giving him a 22.0 average in the four-game sweep -- second on the team behind LeBron James, whose 30-point effort Sunday upped his average to 24.5 this postseason.
Allen was timely with his shots, especially late. Eight of his 16 points came in the fourth quarter.
"He has taken his game to another level and everyone on our team has noticed that," Heat head coach Erik Spoelstra said. "He dove on the floor twice in the fourth quarter and his defense has been improving as well. This is the time of year that brings out another level in him and I'm glad we have him on our side."
After Monta Ellis got Milwaukee to 69-67 with 9:34 to play, Allen answered with a three from the corner to put Miami back up by five, sparking an 18-5 run over the 7:02 that had Miami ahead, 88-72 when Bucks head coach called a 20 second time out with 2:32 remaining.
During that stretch, James scored seven and dished out four assists.
"We knew they were going to come out and play as hard as they could and with as much desperation as they could to try and continue the series," James said. "They made a run and from that point, we were able to execute. Finding Ray, finding Shane [Battier] ... it's good to have the depth that we have so I can draw defenders and find open shooters."
With James leading the way, the rest of the Heat were clicking. Udonis Haslem went 6-of-9 from the field and finished with 13 while Chris Bosh added 10 for Miami, which swept a postseason series for the first time during the Wade-James-Bosh era.
"We're glad to get this, the first step on hopefully a long journey," Spoelstra said. "It's never as easy as it looks but it's gratifying to get something we haven't done before with this group, closing out a team, 4-0."
As good as Miami had been in the series, the Bucks still had chances Sunday to at least steal one game and force fifth game. Milwaukee had a chance to tie the game at the end of the first half when, down 43-41, Luc Richard Mbah Moute overthrew an open J.J. Redick.
Instead, Allen took the steal and found James on the other end for a layup that gave Miami a five-point lead at half. The Bucks threatened again in the third, cutting the deficit to a point early on a Brandon Jennings 3-pointer -- his only basket of the game -- with 9:34 remaining in the quarter.
But Milwaukee committed turnovers on three of its next four possessions as Miami held firm and maintained a five-point lead into the fourth.
"Every time we made some sort of move, we'd make a turnover or they'd make a big play," Bucks head coach Jim Boylan said. "When you play a team as good as Miami is and you make mistakes like that, they usually capitalize on them. And today, they did that."
Ellis led Milwaukee with 21 points on 10-of-20 shooting with eight assists and five rebounds. Off the bench, Redick and Mike Dunleavy combined to go 10-of-20 from the field to finish with 10 and 17 points, respectively but as a team, Milwaukee show 37 percent from the field and made just 6 of 22 3-point attempts while turning the ball over 16 times and lost the rebounding battle, 42-37.
"It's basketball," said Ellis. "They've got a lot of great guys. They got to all the 50/50 plays they needed. When we were getting close, they'd hit shots when they needed to. They have the ability to turn it on and that's what they did. They went out with the lead and came out with the lead."
Jennings, who went just 1-of-7 from the field, sat out the final two minutes of the third and remained on the bench for the entire fourth quarter.
NOTES: Milwaukee's starting backcourt of Brandon Jennings of Monta Ellis shot a combined 41-of-112 (36.6 percent) from the field and just 9-of-47 (19 percent) on 3-point attempts in the series, averaging 27.5 points per game. ... Miami now advances to the Eastern Conference semifinals to face either Brooklyn or Chicago. The Bulls currently lead that series, 3-1. ... The Bucks have lost five consecutive playoff series and 11 of their last 13, dating back to the 1988-89 season. Milwaukee hasn't advanced past the first round reaching the Eastern Conference Finals in 2001 ... Allen made four 3-pointers Sunday and now has 325 for his career during the post-season, the most in NBA history.