DALLAS (AP) — Dallas Stars forward Tyler Seguin was briefly down on the ice with a bloody nose and a bit dazed after taking a shot to the face from Alex Pietrangelo.

That big backhanded swing from Pietrangelo while the two were together against the board was certainly retaliation for the Vegas Golden Knights against Seguin, who earlier in the same period took a penalty for an illegal check to the head of Shea Theodore.

But it was costly for the reigning Stanley Cup champion Knights, who suddenly trail in the opening-round series for the first time. Jason Robertson scored the go-ahead goal on the ensuing power play and the Stars went on to a 3-2 victory in Game 5 on Wednesday night.

“He’s a leader on this team. Playoffs are an emotional time, and it’s a revved-up environment,” Knights defenseman Alec Martinez said of Pietrangelo. “You can’t win without emotion either, but you have to keep it in check.”