Straka began the play by keeping Pittsburgh rookie Evgeni Malkin from taking a breakaway with a fine defensive play. He then deked his way past a defender in the neutral zone to allow New York to set up in the attacking zone.
Seconds later, Straka was at the left edge of the crease for an easy tap-in of a sharp pass by defenceman Michal Rozsival. Jaromir Jagr also scored for the Rangers.
Malkin had Pittsburgh's goal. Pittsburgh played without its other young star, Sidney Crosby, for a third consecutive game. He tested his sore groin in the morning skate Saturday before deciding against a return.
Pittsburgh had taken both previous meetings between the teams this season, including one at Mellon Arena a week ago. Since then, the Rangers have won three in a row, and the Penguins have lost three in a row.
The Penguins had a golden chance to win it 33 seconds into overtime, when New York goaltender Henrik Lundqvist abandoned his net and was at the mercy of Malkin, but his chipped backhander grazed off the right post and skipped wide.
Jordan Staal, an 18-year-old rookie, was awarded a penalty shot at 3:40 of overtime after being hooked on a breakaway by New York defenceman Fedor Tyutin. With the capacity crowd of 17,134 standing in anticipation of victory, Staal failed to register a shot when the puck trickled off his stick on a backhand move.
Jagr had the second assist on the winning goal and finished with two points.
Each team squandered a pair of 5-on-3 power plays before Malkin scored on one 10:35 into the second period. Erik Christensen fed Malkin just to the left of Lundqvist, and Malkin roofed a shot for his 12th goal, most among NHL rookies.
Defenceman Sergei Gonchar had the second assist for his 500th career point.
Jagr tied the game at 12:15 of the third. His deflection of a Karel Rachunek point shot ricocheted off teammate Jason Ward's skate and right back to Jagr, who took advantage of Pittsburgh goaltender Marc-Andre Fleury being out of position for his 12th goal.
Jagr has four goals in his past three games.
Malkin had been questionable because of a hard hit to his left shoulder Thursday, but showed no ill effects of the injury.
Crosby could return for the Penguins' next game Tuesday.
"I'm a lot closer than I was three or four days ago," Crosby said. "I'm just waiting for that turnaround day where I'm not going to feel much at all."