Cooper said special teams have been the difference in the tightly contested series that has included two one-goal games.
"Well you look at Game 1 and the score was 3-2 and a similar one-goal game [Tuesday], so when you look at it that way, the margin of error might be special teams," Cooper said. "The penalty kill might be going a little unnoticed but it's not unnoticed in our locker room."
It's also being noticed by the Red Wings, and players are searching to find answers. Forward Henrik Zetterberg said the unit may need to change its method of attack, and Tomas Tatar said they have to continue to be aggressive.
"I think the problem was a little different than the game before," Tatar said. "The game before we just couldn't get shots through. [Tuesday] it seemed like we couldn't really break in. I think as soon as we settle down in the zone and make the shots through, the power play will start to work because we have enough talent and good shooters here. We just have to establish in the zone and keep shooting pucks."
The Lightning have managed to block many of those shots, 63 through four games.
Tampa Bay is without defenseman Anton Stralman and forward JT Brown, two major parts of the penalty kill, but other players have stepped up and followed the lead of veteran forward Valtteri Filppula, who had a season-high 24:02 of ice time Tuesday, including 4:30 shorthanded.
Cooper said Filppula and Ryan Callahan have been a dynamic penalty-killing pair.
"I want to single out Filppula for his faceoffs; when you are winning some of these penalty-kill draws it takes so much pressure off," Cooper said. "We don't win them all but he's doing an excellent job of helping us there."
When the players on the penalty kill have made a rare mistake, goalie Ben Bishop has made a big save. Bishop has continued his strong play from the regular season and has a .937 save percentage in the Stanley Cup Playoffs.
"When you look at the top goalies in the League and the way Montreal [Canadiens play] in front of Carey Price and the [New York] Rangers play in front of [Henrik] Lundqvist and the [Los Angeles] Kings in front of [Jonathan] Quick, you just go down the line," Cooper said. "There are so many things that help you play the game different because you know what's behind you. And if a mistake is made, more times than not, Bishop is there to clean it up."
