TAMPA, Fla. — Momentum.

The Rangers flew south with it and they headed back home without it.

From the look of the proceedings in the Eastern Conference Final, dating back to Game 2 at the Garden, when the Rangers won a second straight contest and appeared to have taken control of the series, the Blueshirts have awoken the two-time defending Stanley Cup champion Lightning. And that’s a dangerous thing.

The series lead the Rangers took to Tampa evaporated in the suffocating Florida humidity, and after a dreadful 4-1 loss to the Lightning on Tuesday night in Game 4 at Amalie Arena, the series is tied at 2-2.

It has not been a productive three days for the Rangers.

The teams will play Game 5 at the Garden on Thursday night but even with the Rangers still owning home-ice edge, it feels like advantage Lightning, now that Tampa Bay has wrested away the momentum of the series.

Before Game 4, when Rangers coach Gerard Gallant was asked what he was looking for from his team, he emphasized the first period as a key.

“Good, solid first period to start off,’’ he said, “and play our game from there.’’

Gallant got anything but that. The Rangers played on their back feet for the majority of the first period and never recovered. It looked like a continuation of the third period Sunday, when the Rangers conceded to being too passive en route to a 3-2 loss in Game 3.

The first period ended with the Lighting leading 1-0, but the deficit felt greater.

“I don’t think it was an awful first period,’’ Gallant said after the game. “I didn’t think it was a good first period by no means, but we’re playing against a pretty good hockey team that was pretty desperate again tonight down 2-1.’’

The most deceiving element was that the Rangers had outshot the Lightning 10-8 and had won 10 of 18 faceoffs. Stats be damned, it was Tampa Bay that had the most dangerous scoring chances. Had it not been for Rangers goalie Igor Shesterkin, it could have been 3-0 Lightning at the first intermission.

Tampa Bay scored its first goal on a backhander from Pat Maroon, who made a nifty inside move to lose Rangers defenseman Justin Braun in front of the net. Lightning defenseman Zach Bogosian created the play, though, driving the puck into the Rangers’ zone and leaving defenseman Ryan Reaves in his wake. He drew Shesterkin out of the net and made an inside move on Braun.

The first period was everything the Lightning wanted and everything the Rangers had hoped to avoid.

And Lightning goalie, Andrei Vasilevskiy, who gave up nine goals on 62 shots in the first two games, has found his footing.

“He’s getting his mojo back,’’ Lightning coach Jon Cooper said. “If anyone was hurt the most by the [10-day] layoff [before the series], it was him.’’

Before the game, Cooper was asked if he believes in momentum in the playoffs.

“There is momentum in playoffs,” he said. “I think it goes with series. Look at the Rangers. They fell behind in series [against Pittsburgh and Carolina] and built momentum and their team has gotten better as the series have gone on.

“We had to stop the Rangers’ roll. And hopefully [Ondrej Palat’s game-winning] goal with 42 seconds [left in Game 3] put a little pin in their bubble.’’

That Blueshirts’ bubble looked completely deflated Tuesday night.