When injuries continued to ravage the Celtics a few weeks ago, there were whispers that Boston could possibly slip from the No. 2 spot in the Eastern Conference standings, despite their massive lead on the field. Catching the first-place Raptors appeared to be an afterthought.

The Celtics, who in rapid succession lost Daniel Theis, Marcus Smart, and Kyrie Irving for the rest of the regular season, would just use the final few weeks to try to gain some kind of rhythm, and just stay as healthy as they could. On March 18, the Raptors held a five-game lead over Boston with 12 games remaining.

The Celtics did not appear to have the manpower, or even the motivation, to really give chase.

But the Celtics, despite even more absences, have not lost since then, and Toronto has cooled. On Saturday, the Celtics surged to a 110-99 win over the Raptors at a lively TD Garden. It was the sixth win in a row for Boston, which now trails the Raptors by just two games with six left in the regular season.

These teams will meet again in Toronto on Wednesday night, potentially giving the Celtics an opportunity to gain another game, as well as the head-to-head tiebreaker. On Tuesday, Boston will play at Milwaukee, and Toronto will be in Cleveland.

Celtics coach Brad Stevens has insisted he is not overly concerned with claiming the top seed, and he reiterated that stance before Saturday’s game. Raptors coach Dwane Casey, though, emphasized that it is important, and that his team is gunning for it. Regardless of their diverging approaches, it is now a race.

“I think we’re just doing a great job,’’ Celtics forward Marcus Morris said. “We’re not really looking at who we’re playing. We’re just trying to execute things we need to do and better ourselves and get in a great groove.’’

Morris, Jaylen Brown, and Al Horford have all missed games during this unlikely streak, too, but it hasn’t mattered. Stevens, who is now charging toward a possible coach of the year award, has simply made do with whatever is available.

On Saturday, backup point guard Shane Larkin, who has thrived recently, was sidelined with an illness, forcing Stevens to dip into his bag of tricks once more. He turned to unusually large lineups and mixed in more zone defense, just as he did against the Jazz on Wednesday. And just like just about everything Stevens has done recently, it worked.

The Raptors committed seven fourth-quarter turnovers — the Celtics had just six in the entire game — and Toronto missed 26 of its last 31 3-pointers.

“We expected it,’’ Raptors star DeMar DeRozan said of the zone. “But I think it slowed down our momentum offensively. Kind of got a little bit stagnant.’’

The score was tied at 94 with just over five minutes remaining when the Celtics blitzed the Raptors with a game-defining 10-0 run.

Horford started it with a 3-point play, and Morris continued it with a deep 3-pointer from the left arc. After Terry Rozier hit a pair of free throws, Jayson Tatum carved through the lane for a layup that made it 104-94 with 3:22 left. The Raptors were not a threat again.

During this six-game win streak the Celtics have executed quite well, from their late runs against the Trail Blazers and the Jazz, to this.

“We’ve got to, and that’s really important,’’ Stevens said. “It hasn’t been perfect. It wasn’t perfect tonight, but there’s much more good than bad. That’s what we have to be, and guys are committed to that.’’

With 10.9 seconds left and the Celtics leading, 109-99, the Raptors fouled Morris despite the fact that the game’s outcome had been decided. Morris (team-high 25 points) hit one free throw then collected consecutive technical fouls for voicing his displeasure and he was ejected.

He tapped the referee on the rear end and headed off the court, and the TD Garden crowd responded with a standing ovation.

“I just thought the game was over and the foul was a little much,’’ Morris said, “being down 10 with [10] seconds left. Got a little heated.’’

Tatum added 24 points and six rebounds and Rozier had 21 points and seven assists. DeRozan had 32 points to lead the Raptors.

Although the order has yet to be determined, the Celtics and Raptors are guaranteed to occupy the top two spots in the Eastern Conference. If they meet in the playoffs, it will be in the conference finals. So perhaps this was a preview of that.

“It definitely set the tempo,’’ Morris said. “However they want to do it, we can do it.’’

The Celtics’ Aron Baynes, who had been 0 for 12 on 3-pointers this season and had made just one during his NBA career, supplied an improbable lift by starting 5 for 6, including a pair of 3-pointers. The Celtics needed this hot start, as the Raptors went 14 for 23 in the opening quarter.

After Baynes’s streak ended, Rozier stepped in. Over a 90-second stretch the point guard hit two driving layups and a step-back 3-pointer, helping Boston pull within 33-31.

At the start of the second quarter Stevens went with a lineup that featured rookie guard Kadeem Allen, one of Boston’s two-way contract players, surrounded by big men Horford, Morris, Greg Monroe, and Semi Ojeleye. It was unorthodox, but Stevens was also left with little choice.

The Raptors finished the first half shooting 52.5 percent but led just 55-53 at the break.

Boston went with an even bigger lineup late in the third quarter, with Horford, Tatum, Morris, Monroe, and rookie forward Abdel Nader.

Tatum used his length atop the zone defense to fluster Toronto’s smaller guards; at the other end, he attacked mismatches, like when he blew past 5-foot-11-inch Fred VanVleet­ for a layup that gave Boston an 84-82 lead.

“With Tatum at the top of that, that’s a pretty good guard at the top of the 2-3 zone, when he puts his arms out,’’ Stevens said.

Adam Himmelsbach can be reached at adam.himmelsbach @globe.com. Follow him on Twitter @adamhimmelsbach.