INDIANAPOLIS -- When the Boston Celtics absolutely needed him, Isaiah Thomas came to their rescue Saturday night.

While he made only 4 of 13 field goal attempts, Thomas scored 12 of his 23 points during the final 4:19 and the Celtics defeated the Indiana Pacers 105-99 in Bankers Life Fieldhouse.

Thomas led Boston (5-4) and Kelly Olynyk added 16 points, helping the Celtics hand the Paul George-less Pacers (4-6) their first home defeat.

George, who is averaging 21.9 points, suffered a sprained left ankle in Friday night's overtime loss at Philadelphia and could not play.

Jeff Teague led Indiana with 20 points and Myles Turner added 17, but the Pacers had no answer for Thomas, who was 6 of 6 from the free throw line during the final 1:22 and finished 14 of 15 for the game. Thomas came in averaging 26.1 points.

"That is what the game is all about - the fourth quarter," Celtics guard Avery Bradley said of Thomas' final 4:19. "Isaiah did a lot for our team tonight, even though he was not shooting well. He created shots for other players and helped out by just penetrating and collapsing the defense."

CJ Miles' 3-pointer with 23 seconds remaining pulled Indiana within 103-99, but two Thomas free throws with 20.5 seconds to go iced it.

The Pacers were outscored 27-21 from the free throw line and made only 6 of 27 shots from 3-point range.

Boston also outrebounded Indiana 47-40. In their past two games, the Pacers have made only 11 of 46 shots from beyond the arc (23.9 percent).

George, who said he sprained his ankle late in the fourth quarter at Philadelphia, felt helpless watching his team's four-game home winning streak end.

"It was real frustrating, especially at home against a good team," George said, "The problems tonight were some of the same ones we have been having. I just thought we were real stagnant on offense."

In addition to losing George, Indiana coach Nate McMillan said it was evident both teams were playing the back ends of back to back nights.

"We were slow getting into our offense, and because of that, we were always fighting the shot clock," McMillan said, "Both teams had heavy legs. You want the opponent to have to defend your first or second option, and we didn't do that. Instead, we just took a lot of quick shots. The other thing was they were running around our bigs, making them defend 3-point shooters."

James Young's 3-pointer from the right corner with two seconds remaining gave Boston a 79-76 lead at the end of three quarters. The Pacers led by as many as five in the quarter, but Thomas and Young combined for 18 third-quarter points, helping the Celtics maintain their halftime advantage.

"One of the things I told James on Friday was to be ready, and then he never got in," Boston coach and Indiana native Brad Stevens said. "I told him one of these two games, he would be very impactful. He shot the ball at such a different level tonight then when he got here two years ago. He has worked really hard on his accuracy."

Stevens said George sitting out did not affect how the Celtics were trying to play.

"We were down a few players too," Stevens said. "But you knew Teague, Monta Ellis and Aaron Brooks would be real aggressive with him out."

Teague, Ellis and Brooks were a collective 12 of 33 from the field.

Boston made only 7 of 17 shots from the field in the third quarter but was 13 of 16 from the free throw line in the quarter.

Trailing 45-35 with 3:33 remaining in the second quarter, the Celtics finished the first half on a 13-0 run, which included three 3-pointers, and led 48-45 through 24 minutes.

Olynyk had 12 points, five rebounds and three assists to lead the Celtics at halftime, and Amir Johnson and Terry Rozier each added eight.

NOTES: The Celtics were without C Al Horford (concussion protocol) and F Jae Crowder (left ankle sprain). ... The Pacers were without G Rodney Stuckey (right hamstring sprain). ... Each team was playing the second game of a back to back. Boston defeated New York 115-87 on Friday night and Indiana dropped a 109-105 overtime game at Philadelphia. ... The Pacers entered this game ranked 29th in scoring defense (112.8) and the Celtics came in ranked 27th (109.5). ... Boston is second in assists (26.4) and Indiana is third in opponents' turnovers (16.9). ... The Pacers won last season's series 3-1 and have won five of six most recent regular-season meetings. ... Indiana G CJ Miles came in shooting 52.4 percent (22 of 42) from 3-point range. ... The Pacers' Paul George, Myles Turner and Jeff Teague each has had a game high of 30 points.