"Today was just a great day," Young said. "My teammates were looking for me and they put me in different positions."
Bosh returned from a seven-game absence to finish with 12 points and 12 rebounds, but the Raptors still lost for the fifth time in six games.
"They were more focused than we were," Bosh said.
Raptors coach Jay Triano was more blunt.
"We weren't very good," Triano said.
Bosh was back after being sidelined for six games with a sprained left ankle and missing Friday's win over New York with a severe stomach virus that forced him to spend several hours in a hospital. He was briefly knocked out of this one after falling early in the fourth but returned to the court after getting his ankle re-taped.
"I felt pretty good," Bosh said. "It's going to take some time. I've still got to get my legs under me. Once I get my legs and my strength back, I think I'll be fine."
The Raptors, however, aren't so fine, and find themselves struggling to hold on to a playoff spot as they depart for a four-game West Coast trip.
"We've got to do a better job of getting our minds ready for the games," guard Antoine Wright said. "I don't know what it's going to take but something has to happen right now because we can't afford to lose games like this.
"There's not that much margin for error right now," Wright added. "You lose a game like this, you can go from fifth to seventh or even eighth. You don't want to be fighting to get back in the hunt. We've got to figure some things out."
The 76ers went 9 for 12 from 3-point range, including three by Young.
"Thad made his 3's and I felt that jump-started us," 76ers coach Eddie Jordan said.
Jarrett Jack had 20 points and nine assists for Toronto.
Iguodala gave a meaningful look at the Raptors bench after his fadeaway jumper in the fourth quarter put the 76ers up nine points, 96-87.
"Guys were talking trash behind me as I was going up," Iguodala said. "[Former 76ers forward Reggie Evans] is one of those guys that talks a lot of trash. He was beating us up a little bit when he was in the game so I had to try and get him back somehow."
Jose Calderon made a 3-pointer to get Toronto within six, but Williams answered with a layup. Holiday then made a 3-pointer from the corner and converted a driving layup to increase Philadelphia's lead to 107-94 with 2:33 left.
Young started in place of Samuel Dalembert, who began the game on the sideline after arriving late to a team meeting before the tip. Dalembert had started every game this season.
"It was pretty early but that's OK, everybody else showed up," Jordan said.
Philadelphia's Marreese Speights had to be helped to the locker room after spraining his right knee in the second quarter. Speights was driving to the basket when he stepped on Bosh's foot, then fell over and lay on the court clutching his knee. X-rays were negative but Speights did not return.
The 76ers closed the second quarter with a 7-0 run to take a 55-47 lead into halftime.
Young's previous career high was 31, against Chicago on March 13, 2009. ... Calderon received a technical foul for arguing in the second. ... The 76ers had 15 assists on 23 field goals in the first half. ... Bosh did not attempt a free throw for just the second time this season.