Barbosa scored a season-high 29, Ed Davis had 12 points and 13 rebounds and the Raptors beat the Pacers 108-98 on Friday night, Indiana's fifth straight loss in Toronto.
The Pacers lost their sixth straight overall and dropped into a tie with Charlotte for the final playoff spot in the East after the Bobcats beat Portland.
As upset as they were at themselves after another poor effort, the Pacers were angrier at Toronto after Barbosa drove to the basket with six seconds left and his team leading by 10 points.
"If I was on him, I would have took his head off and I would have been suspended for a game for a flagrant foul," Danny Granger fumed. "Stuff like that will sit in the back of your head the next time we play Toronto. We don't play them again but if I was on him, I would have taken his neck off."
The Raptors said the shot was payback for a play at the end of Toronto's 104-93 loss in Indianapolis on Jan. 31, when Darren Collison hit a late 3-pointer.
"You can't give respect if you don't [get] respect," Barbosa explained.
Granger said he didn't recall the original incident.
"I can't remember but, like I said, it'll sit in the back of your mind next time you play Toronto," he said. "That's unsportsmanlike. I would have taken his head off and busted his lip. That's just me though."
Barbosa said he knew the Pacers were going to get mad about his shot, adding that he considered the exchange finished.
"For us, it's even," Barbosa said. "We won't do that anymore if they don't do it."
Calderon had 13 points and eight assists for Toronto while Reggie Evans had 16 rebounds.
Andrea Bargnani returned after sitting out Wednesday's loss to Utah with flulike symptoms but missed his first eight shots and finished 1 for 13 with eight points.
Since winning seven of its first eight games under coach Frank Vogel, Indiana has lost 10 of 13.
"Our defense let us down," Vogel said. "And when we did get stops, we didn't rebound the ball. We've got to do better in those two areas."
After losses to Minnesota and Toronto, Indiana will face tougher opposition in its next five games, facing New York twice, Boston, Chicago and Memphis.
"It's not going to get any easier," Granger said. "We really let ourselves down, we really dropped the ball. We had a few teams that we should have beaten and we didn't. Now we've got playoff teams. It's probably one of the hardest stretches we'll play this year. We've got to buckle down or we're going to miss this playoff spot."
Ahead by 10 to start the fourth, Toronto stretched its lead to 15 on a 3 by Sonny Weems with 7:45 remaining. But Indiana answered with a 7-0 spurt, including five points from Granger, making it 97-89 with 6:08 left.
Barbosa stopped the run with a 3-pointer but George replied with a 3 and Josh McRoberts added a layup, cutting it to 100-94, before back-to-back jumpers by Davis and DeRozan restored Toronto's double-digit lead with 2:48 left.
Granger made a layup and Collison hit two free throws to make it a six-point game. After a Toronto miss, Bargnani came up with a key rebound and Calderon drove for a layup with 30 seconds left to make it 106-98. After a Granger miss, Calderon capped it with a pair of free throws.
Toronto opened the second with an 11-2 spurt and Indiana called timeout after Barbosa's 3 made it 43-29 with 9:56 to go in the half. Barbosa scored 13 in the second as the Raptors led 62-48 at the break.
Collison scored nine points and Hansbrough had six in the third as Indiana halved its deficit, drawing to 74-67 with 4:13 left in the quarter. But the Raptors held firm, taking an 83-73 lead into the final quarter.
Toronto's Amir Johnson, who left Wednesday's game with a sprained left ankle, was inactive but said he could play Sunday when the Raptors host Charlotte. Davis took Johnson's spot in the starting lineup. ... Raptors C Alexis Ajinca (right knee) missed his second straight game. ... Foster returned for Indiana after missing Wednesday's loss with a sore back.