BOSTON -- Al Horford likes what he sees from his team as it steams toward the NBA playoffs.

"I think the guys are starting to understand that we're playing for bigger things and we have a chance to ... to see what we can do," Horford said after his Boston Celtics cruised to a 109-100 victory over the Indiana Pacers on Wednesday night.

The win, coming in Boston's first game after clinching a playoff spot while idle Tuesday, completed a three-game sweep of the season series with the Pacers. Side note: The last time that happened, in 2007-08, the Celtics won the NBA championship.

The still-growing team would be, at best, an extreme long shot to do something like that again, but this team is alive in the chase for the No. 1 spot in the Eastern Conference. Their win and the Cleveland Cavaliers' loss at Denver cut the lead down to a game -- two in the loss column.

The Celtics, 2 1/2 games ahead of the Washington Wizards for the second spot in the conference, are 25-9 at home and have won 12 of their last 13 at TD Garden and Wednesday was the second game of a six-game homestand for a team with only three road games remaining.

"I've been looking forward to this home stretch all season," said Horford, who had another strong game. "When I looked at it, I was like, 'Man, I can't wait.'"

The Celtics opened a seven-point lead at the half and took over from there.

The Celtics took a 17-point lead early in the fourth quarter before an Indiana 10-0 run that grew to 13-2 got the deficit down to six. The visitors then went cold the rest of the way.

Isaiah Thomas scored 25 points and dished out five assists, and Avery Bradley had 18 points and eight rebounds for the Celtics. Al Horford had 15 points, eight rebounds and eight assists, Jae Crowder recorded 15 points and six boards, and Kelly Olynyk registered 11 points and eight boards for Boston (46-26).

"We're playing the right way right now," said Bradley, who logged 39 minutes and later said, "Not even tired."

"Every team is playing hard right now and it's our job to continue to keep playing the right way and trying to prepare for the playoffs," he said. "We're almost there. We're close."

Horford is averaging 18.4 points, 8.4 rebounds, 6.2 assists and 2.0 blocks over the last five games.

Paul George led the Pacers (36-35) with 37 points and Jeff Teague had 25 points and six assists. They were the only two Indiana players in double figures.

"They started getting away from us and I tried to keep the game as close as possible," said George, who played the entire second half and was 11 of 26 from the floor, 5 of 13 from 3-point range in coming within two points of his season high.

"I felt the direction and the way the game was going, we were at a standstill and I thought it was the opportunity to be aggressive and will us closer heading into the fourth."

The loss dropped the Pacers, who are sixth in the East, to 7-8 in their last 15 games -- alternating wins and losses throughout the 15 games.

"You talk about strong starts and strong finishes," said McMillan. "In the first and third quarters, we got off to slow starts. They came out very aggressive in the third quarter, hitting three or four straight threes.

"They got the momentum and kept the momentum."

The Pacers did get a solid contribution from Lavoy Allen off the bench. He played 21:40 and grabbed 14 rebounds, nine on the offensive end, while scoring eight points.

The Celtics turned the ball over 14 times in the first half but only three more times after the break.

"We took care of the ball better and Allen got every rebound on the court," said Celtics coach Brad Stevens. "So one of these days we'll put one of these together."

NOTES: Celtics assistant coach Micah Shrewsberry reportedly interviewed for the vacant UMass coaching job. ... G Isaiah Thomas extended his club record with a trey in his 46th straight game. He also registered his 120th straight double-figure scoring game, the first Celtic to do that since Antoine Walker had 126 starting March 31, 2000 and ending Jan. 11, 2002. Thomas is also closing in on Walker's team record of 222 3-pointers set in 2001-02, finishing the game with 213. ... The Celtics are 20-0 when leading after three quarters at home. ... Boston G Avery Bradley reached the 100 3-pointer plateau for the third straight season after missing it his first four. ... The Pacers open a three-game homestand against the Denver Nuggets on Friday night, while the Celtics play the third of sixth straight at home when the Phoenix Suns visit.