It showed in Game 1 of the Eastern Conference final, when the tentative Lightning couldn't hang with the playoff-tested New York Rangers.
"It's just part of the evolution of our team," Cooper said Sunday. "But we're not going away. We're going to hang around, and we've just got to keep building on these experiences and learn."
The Lightning didn't just hang around in Game 2 on Monday night. They beat up, banged around and blew out the Rangers 6-2 to steal a game at Madison Square Garden.
More importantly, the Lightning made a convincing statement that they're not just happy to be in the conference final. They belong on the same ice as the Presidents' Trophy winners.
"No one was doubting that, but I think this maybe reinforces it a bit," forward Alex Killorn said.
Mentally, no one could blame the Lightning for being tired and letting some doubt seep in. They had to battle back to beat the Detroit Red Wings in the first round and learned a tough lesson about closing out a series when a 3-0 series lead on the Montreal Canadiens quickly became 3-2.
With only two players back from the 2011 trip to the conference final, forward Steven Stamkos and defenceman Victor Hedman, each series and game is a new lesson. While the first game of the Detroit series was evidence a team can play well and lose, Stamkos saw Game 1 against New York as one where the Lightning played "like crap" and had to respond.
"We're here," Stamkos said Monday afternoon. "You don't get many chances to be at this stage in the playoffs. Some people are more fortunate than others, but we have to have a belief that this is our year, and we need to play better."
And they were better with a six-goal outburst, led by Tyler Johnson's hat trick. Tampa Bay wasn't necessarily even at the top of its game but was opportunistic scoring three times on the power play and once short-handed.
It was the kind of showing that led Rangers captain Ryan McDonagh to call his team's performance "embarrassing." Sure, New York made plenty of game-defining errors, but the Lightning looked like an entirely different team than two days earlier.
"I think in Game 1, we participated in the hockey game, and in Game 2 we came to win a hockey game," Cooper said. "That was the difference."
The difference between a 2-0 series and 1-1 series is substantial, especially considering the Rangers haven't taken the first two games at home since 1994. This current core has now split the first two games at Madison Square Garden in nine different chances dating to 2011.
But the Rangers have also proven they can win in the playoffs, most notably reaching last year's Stanley Cup final. Cooper saw Game 1 of the East final as one team that had been there before and another that hadn't.
Stamkos has been there before and made it clear that youth wasn't going to keep the Lightning from standing up to the Rangers.
"Everyone said we were too inexperienced this year with the young group that we had, being swept last year. Well, we learned from that pretty quick," Stamkos said. "We know how to win, too."
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