At 19:44 of the first period in the Blackhawks/Penguins game, Pittsburgh requested a Coach's Challenge to review whether Chicago was off-side prior to Marian Hossa's goal.
After NHL Hockey Operations staff reviewed all available replays and consulted with the linesmen, the call on the ice was upheld -good goal Chicago Blackhawks.
Coach's Challenge: CHI @ PIT - 19:44 of First Period
Call on the ice was upheld, good goal Chicago