Christensen added an assist, and Michel Ouellet had a goal and an assist for Pittsburgh, who passed the Islanders and moved into third place in the Atlantic Division with their second straight win. Richard Park and Arron Asham scored for New York.
Crosby, who had no shots and a minus-1 rating through two periods, had two goals in the third period on rebounds. His power-play goal with 16:32 left off Ouellet's shot gave the Penguins a 3-2 lead. Crosby's second on a rebound of Mark Recchi's shot with 6:15 left put the game away.
Christensen scored the game's first goal 2:32 in with a nifty backhand move from the slot on a pass from Maxime Talbot.