TORONTO -- Philadelphia 76ers coach Doug Collins has been working long hours trying to figure out his new team. Like their coach, Collins' players put in some overtime Wednesday night.
DeRozan, who missed a potential winning free throw at the end of the first overtime, converted a hook shot and Amir Johnson added a dunk to help the Raptors (2-2) snap a two-game losing streak.
Philadelphia's Louis Williams saw his a 3-pointer rim out in the final seconds as the 76ers lost for the fourth time in five preseason games.
Raptors guard Jarrett Jack, who scored 24 points, was just happy to see it end.
"Thank goodness it's over," Jack said. "They're cutting into our day off."
Despite the loss, Collins said each game is a chance to learn something else about the team he took over in May.
"I'm trying to figure this team out," Collins said. "I'm still trying to figure who can do what in what situations and it's going to continue to take me every single day. I work 12 to 14 hours a day trying to find out the best things I can do."
Leandro Barbosa scored 19 points for Toronto, DeRozan had 16 and Andrea Bargnani 14.
Jrue Holiday had a triple-double for Philadelphia, finishing with 18 points, 12 assists and 11 rebounds. Holiday played 32 minutes Tuesday in a victory against Boston, then almost 46 minutes more in this one.
"My feet hurt a little bit but I'm good," Holiday said.
"We're trying to change something around here," Holiday said of the 76ers, who went 27-55 last season. "We've have Coach's back and Coach has our back. The least we can do is go out there and play hard for him."
Rookie Craig Brackins scored 15 points for the 76ers, Evan Turner added 13 points and 12 rebounds, Elton Brand and Jodie Meeks each had 12 points, and Williams finished with 10.
Toronto led 95-90 on a jump shot by Jose Calderon with 3:01 left in regulation, but Philadelphia tied it at 96 on a dunk by Brackins with 1:24 left.
An errant pass by Jose Calderon gave the 76ers one last shot with 5.5 seconds left but Holiday's 3-pointer came up short, sending the game to overtime.
Bargnani scored on Toronto's first two possessions of the first extra session but missed two from the line before the Sixers rallied. Holiday hit a jumper with 49 seconds left to give Philadelphia a 103-102 lead, its first since the third quarter.
Jack and Meeks traded 3-pointers before former Raptors guard Jason Kapono fouled out with 1.8 seconds left, sending DeRozan to the line. He made the first but missed the second and Bargnani could not put back the rebound, sending it to double overtime tied at 106.
A driving layup by Williams made it 116-115 with 1:25 left before DeRozan's hook shot in the paint gave Toronto the lead for good.
Bargnani, the top pick in the 2006 draft, came in 5 for 26 from the field in Toronto's first three preseason games. He struggled again in this one, shooting 6 for 22.
Raptors forward Linas Kleiza returned to the starting lineup after sitting out a loss Tuesday at Chicago with a sore right Achilles' tendon and scored six points in 17 minutes.
Sixers forward Marreese Speights left with 4.6 seconds remaining in the third with an injured right hamstring. He walked gingerly to the locker room with the help of a team trainer and did not return.
"I think he's OK," Collins said. "We have a day off tomorrow so we'll see."
Philadelphia center Spencer Hawes (lower back) missed his fourth consecutive game. ... The 76ers are idle for five days before their next preseason game, Oct. 19 at Cleveland. Toronto hosts Boston on Friday night. ... This was the first double-overtime preseason game in Raptors history. ... Actor Rob Lowe attended the game.