The Sharks pushed hard late in regulation and at the start of overtime for their best stretch of play since the second period of Game 1, but couldn't find a way to put the go-ahead goal past Penguins goaltender Matt Murray.
Then Sheary scored the winner off a set faceoff play that started with Sidney Crosby winning the left circle draw cleanly from Ward.
"We scored to tie it up. We did something," Couture said. "I thought we created some chances there in the last couple minutes to give ourselves a chance to win. Unfortunately, it didn't find a way in the back of the net."
The Sharks are at least a little bit frustrated. That was evident in Couture's postgame accusation that Crosby "cheats" on faceoffs and "gets away with it [because] he's Sidney Crosby."
The Sharks' power play carried them to the Western Conference championship, scoring on 27 percent of its opportunities through the first three rounds. But it has been limited to three opportunities in the first two games against the Penguins, including one in Game 2.
Although that's partly because of the Penguins being disciplined, it's also because the Sharks don't have the puck enough in dangerous situations to force the Penguins into taking penalties.
"I thought we were better tonight, but we've got to find a way to create some more space 5-on-5 and some more 5-on-5 offense because they're not taking penalties," DeBoer said. "So, we've got to find a way to do this 5-on-5 or push them into taking some more penalties."