Tlusty's goals came 35 seconds apart during a four-goal Maple Leafs flurry in the third period.
Alexander Steen scored Toronto's first goal and had two assists. Mats Sundin added two assists and was largely responsible for shifting the momentum the Maple Leafs' way after the Penguins kept a 1-0 lead for half the game.
Sidney Crosby scored his third goal, all against Toronto, and assisted on a goal by Sergei Gonchar that came during a two-man advantage in the third, but the Penguins lost for the second time in six games.
The Maple Leafs, the league's worst defensive team so far this season, tied it 1-1 midway through the second when Sundin, whose strong play at both ends created numerous scoring chances, helped set up Steen's second goal.
Tlusty, who had been playing for the American Hockey League's Toronto Marlies, gave the Maple Leafs the lead at 2-1 by setting up in front of goalie Marc-Andre Fleury and deflecting a Steen 35-footer that sailed over Fleury's left shoulder with one minute, 45 seconds gone in the third. Steen was initially credited with the goal.
As a result, Tlusty thought he had scored his first career goal 35 seconds later with a strong wrist shot from the left faceoff circle dot that Fleury had no chance of stopping. Pavel Kubina assisted on both of Tlusty's goals.
Tlusty was so excited when general manager John Ferguson called him at 1:30 a.m. Wednesday to tell him to report to the Maple Leafs' practice later that day, he never went back to sleep. The third player called up by the Leafs this week, Tlusty made an immediate impact on a team that had allowed 22 goals while losing four of its previous five.
Toronto, previously 0-4-1 against Pittsburgh the last two seasons, again scored twice barely 30 seconds apart midway through the final period with Tomas Kaberle getting his third at 10:02 and Boyd Devereaux scoring his first at 10:35.
Fleury had turned aside 66 of 67 shots in winning his last two starts, only to give up five goals on 27 shots during a ragged performance. Toronto goalie Vesa Toskala made 23 saves.
Penguins centre Maxime Talbot plowed face-first into the right-wing boards in the Toronto end while trying to deliver a check on Ian White late in the first period. Talbot lay on the ice for a few moments before getting up and did not return to the game. The team said only that he had a neck injury.
Notes: Penguins coach Michel Therrien switched up his lines, with last season's rookie of the year, Evgeni Malkin, playing with Crosby for the first time. Both are natural centres. ... Pittsburgh was 12-2-2 in its previous 16 against original six clubs. ... Toronto had allowed five goals or more in four of its previous five games. ... Toronto won on the road for the first time in three games (1-1-1). The Maple Leafs began a stretch of six of seven on the road. ... Pittsburgh has scored a power-play goal in all nine games. ... Penguins RW Mark Recchi hasn't scored a goal since the opener despite playing most of the season on Crosby's line.