The last time the Boston Celtics won 59 games - in 1986-87 - was also the last season they swept the Chicago Bulls.

Both could occur again at the United Center on Tuesday, when the Celtics look to move a step closer to clinching the NBA's best record while damaging the Bulls' slim playoff hopes.

The Celtics (58-15) have already won more games than they did in the last two seasons combined, and they've dominated the Bulls in the process, earning three wins by an average of nearly 20 points.

They had lost eight straight versus Chicago (29-44) coming into 2007-08, and haven't swept the Bulls in a season since going 6-0 against them in 1986-87 - also the last time the Celtics advanced to the NBA finals.

After beating Miami 88-62 on Sunday, Boston enters Tuesday's game with a magic number of three to clinch the league's best record. The Celtics hold a six-game lead and the head-to-head tiebreaker over Detroit with nine games left.

The Celtics, who lead the NBA in field-goal percentage defense and points allowed, permitted just 17 field goals against the lowly Heat - a record for the shot-clock era. The previous mark of 18 was held by the 1998-99 Bulls.

"We are trying to prepare and get ourselves ready for the playoffs," Boston's Kevin Garnett said. "The competition is what should motivate you. We definitely didn't want to lose the game, or mess around. So we just came out aggressive and never looked back."

Boston could use a similar outlook in its upcoming games. The Celtics close the season with eight of their last nine against teams with losing records.

That group includes the Bulls, who are fading from contention for the East's final playoff spot. Celtics coach Doc Rivers, though, is wary of a possible first-round matchup with Chicago.

"You can have one of those (seasons) and then get in the playoffs and be dangerous," Rivers told the Celtics' official Web site. "The regular season hasn't gone the way they wanted it to, but if they can sneak into the playoffs, they're gonna try to be a factor."

The Bulls beat Milwaukee 114-111 on Saturday after losing four of their previous five games. Even beating the Bucks wasn't easy despite a 21-point lead in the fourth quarter. Milwaukee went on a 19-2 run to make the game close, but the Bulls - who had seven players score in double figures - held on.

"For some reason that's something that we've been struggling with all season," said center Joakim Noah, who had 18 points and 15 rebounds. "I think it's all about being on the same page. We pulled together at the end and we got stops when we needed them. But I think we just have to do a better job of more consistent defense for 12 minutes, especially in the fourth quarter."

The Celtics' defense has been the difference against Chicago this season. The Bulls have averaged 85.3 points and shot 34.4 percent versus Boston, making just 31.8 percent from the field in a 116-93 loss March 7.

Boston won 92-81 at the United Center on Dec. 8.

Copyright 2007 by STATS LLC and Associated Press. Any commercial use or distribution without the express written consent of STATS LLC and Associated Press is strictly prohibited