If they don't step it up, the slumping Toronto Raptors could be in danger of losing control of the Atlantic Division.
Things aren't about to get any easier in Boston, where they haven't won in over six years.
The Raptors try to avoid a 12th consecutive road loss to the Celtics as these teams open a home-and-home set Wednesday night.
Toronto (39-31) is coming off Tuesday's 102-100 loss at Cleveland, its fourth defeat in six games. The Raptors are still all but certain to make the playoffs for the first time since 2007-08, but they suddenly find themselves just 1 1/2 games ahead of second-place Brooklyn with three weeks left in the regular season.
"We're not good enough to scoreboard watch," coach Dwane Casey said. "We've got to take care of our business at hand. If we don't do that, we're not going to out-talent anybody by just showing up and showing our press clippings. We've got to come out and do all the dirty work, be a desperate team, play that way or we struggle."
Kyle Lowry had 22 points and 10 assists for Toronto, which trailed by as many as 21 before rallying late. The Raptors had a chance to tie with 1.9 seconds left, but Greivis Vasquez turned the ball over after losing his footing.
"I'll take responsibility. I'm not going to run away. I'm a man," Vasquez said. "I wish I could be in that position again so we have another opportunity (Wednesday)."
Toronto and Boston have split two meetings this season, with each winning at home. Celtics forward Jared Sullinger had 25 points and a career-high 20 rebounds and Avery Bradley scored 20 as Boston held on for an 88-83 victory Jan. 15.
The Raptors have dropped 20 of 22 in Boston, including 11 straight by an average of 15.2 points. Their last road win over the Celtics came Jan. 23, 2008.
"It's easy to get up for OKC, Miami and Indiana, but the other teams are playing for something too, which is pride," said Casey, whose team hosts Boston on Friday. "That can be even more dangerous."
While the Celtics don't have much to play for, they know Toronto has plenty at stake.
"We know we've got to make adjustments when we play a team back-to-back and this is a team that wants to win the Atlantic Division, so it's going to be a scrappy game," Sullinger told the team's official website. "Win or lose, we don't have to think about the next team we play. We just know that we play Toronto. Watch the game film and do your analysis from there."
The Celtics (23-47) will take the court for the first time since Friday's 114-98 loss at Brooklyn, their sixth defeat in seven games. Bradley matched a career high with 28 points, but Boston allowed the Nets to shoot 56.4 percent.
"We weren't very good on the defensive end of the floor. When Avery Bradley started going off, we just accepted trading baskets instead of really getting stops," said coach Brad Stevens, whose team was outscored 62-30 in the paint.
Rajon Rondo has recorded a 72-10 assist-to-turnover ratio over his last six games. He's averaged just 9.0 points while shooting 29.9 percent during that stretch, though.