Pittsburgh superstar Sidney Crosby had two goals and an assist, giving him 11 points over his last three games.
The Penguins became the first team in the NHL to reach 20 victories this season and they increased their lead in the Atlantic Division over New Jersey to five points.
Crosby tied the game with 7 seconds left in the first period and it remained a 1-1 deadlock until Guerin scored on the power play early in the third.
Jordan Staal and Crosby each scored into an empty net during the final minute. Crosby's goal total reached 19.
Marc-Andre Fleury had to make only 15 saves to pick up his 17th win of the season. Peter Budaj, making his first start since Nov. 18, stopped 29 shots. Budaj was filling in for Craig Anderson, who suffered a neck strain on Wednesday during a loss to Florida.