After two grisly outings that had seen them fall behind the Pittsburgh Penguins2-1 in the series, the Lightning were desperate for some pushback. And they were desperate for it to be shown early.
Enter the rugged Callahan, who scored on the first shift of Game 4, 27 seconds in, deflecting a Victor Hedman shot past Pittsburgh goalie Matt Murray for a 1-0 lead en route to a 4-3 victory that reduces the conference finals to a best-of-three competition at two wins apiece.
Game 5 is set for Sunday in Pittsburgh at 8 p.m. ET.
"That's the start we needed," Lightning head coach Jon Cooper said. "You want your team to make a push. You want them to say, 'OK, we're making a stand. We got embarrassed at home in Game 3, let's make a stand.' And you can't ask for anything more than Callahan scores on the first shift at 27 seconds in.
"I don't think anybody'd sat down yet, and they didn't need to. The energy in the building after we scored, it just pushed, and we carried that through. You can't say enough about Ryan Callahan and his positive effect on our team."
The storyline heading into Game 4: What kind of pushback, if any, did the Lightning have after they were basically schooled in Games 2 and 3 by a wickedly fast, explosive Penguins team?
Lose Game 4 and say goodnight: Zero chance the Lightning win three in a row against the Penguins.
And while continuing to play without top goalie Ben Bishop and captain Steven Stamkos, this was really a test of character for Tampa Bay.
That it was Callahan, the former New York Ranger, who delivered the goods in so many areas shouldn't come as much of a surprise to anyone who has spent any time around him.
"It was good to get him back going the way he's capable of," veteran Lightning defenseman Matt Carle said. "He's a huge part of our team. Even on the nights that he's not on the score sheet, he's still making a difference. I don't know how many times I played against him when he was in New York [and I was] in Philly. You always knew when he was on the ice and generating a forecheck, getting in on the forecheck. He's a hard guy to play against and certainly a guy you like having on your team."
Callahan is that rare but invaluable player whose value is sometimes hard to quantify.
If you have a guy who scores 40 goals, you can figure out what is good value in terms of contract and term.
A guy like Callahan is different. The intangibles, the will to win, the hardness of his game, the willingness to play without compromise, those are harder to get a handle on.
When Callahan was acquired from the New York Rangers by the Lightning in exchange for disgruntled Martin St. Louis at the 2014 trade deadline and then signed to a six-year contract extension that summer with an average cap hit of $5.8 million, there were more than a few arched eyebrows.
Even now, hockey people talk about how difficult that contract is going to be in the final years, given how hard Callahan plays the game -- meaning injuries and wear and tear might eventually reduce his effectiveness.
But on a night like this, we're guessing Tampa Bay general manager Steve Yzerman is at peace with his decision.
Not only did Callahan score the game's first goal to spark the Lightning to what would become a 4-0 lead through 40 minutes of play, he was a beast all over the ice.
He led all players with five shots on goal in the first period.
He blocked three shots on the night, tied for the game lead, including getting in front of an Evgeni Malkin blast on a penalty kill.
"He was awesome, you know," Lightning forward Ondrej Palat said. "I think the team were feeding off his energy and we were trying to follow him, because he had a great start, he scored and he was all over the place. He was making plays. He was great tonight and we were trying to follow him."
Callahan, the former captain of the Rangers, admitted he had more jump in Game 4 than he had previously in the series. And he noted that given the Penguins' depth -- they did score three times in the third and narrowly missed completely erasing the four-goal Lightning lead, thanks in large part to that depth -- it's imperative the Lightning get contributions from up and down their lineup as well.
As for his ability to annoy opposing players, Callahan insisted that's not his goal.
"I don't necessarily go out there and say I'm going to try to get under the other guy's skin," Callahan said. "I go out there and play my game and try to finish my checks, go to those dirty areas. Playing against guys like that, sometimes that can frustrate, knowing that the player's always coming at you."
By the time Callahan, 31, gets to the end of this contract, maybe there will be times when people will shake their heads and wonder what on earth the Lightning were thinking.
They probably won't remember this night, one when the team needed a win to breathe life into their dreams of a Stanley Cup championship. Not that Callahan's teammates will have any trouble remembering this night -- and his role in it.