The Capitals join hero Mike Green in celebrating the overtime goal to beat Tampa Bay at Verizon Center. (Greg Fiume/GETTY IMAGES)

Twenty-six minutes into Saturday night’s game at Verizon Center the Washington Capitals appeared unstoppable. In possession of a four-goal lead against a wayward Tampa Bay Lightning squad, the Caps were cruising toward their seventh consecutive victory.

Then the Capitals lost sight of their game, let up, allowed Tampa Bay to score four consecutive goals and push a game that seemed like an automatic victory to overtime.

Mike Green made sure the blown lead wouldn’t be a costly lesson. With 2 minutes 59 seconds gone in overtime, Green blasted a slap shot from the top of the circles on a power play past Tampa Bay netminder Mathieu Garon, giving the Capitals a crucial 6-5 win.

“We got the two points but how we play in the third period, we can’t do like that,” said Alex Ovechkin, who recorded a goal and assist in the win and now has 24 points in the past 15 games and leads the NHL in goals scored. “We can’t give team that skilled [those] kind of opportunities out there. It’s just embarrassing.”

While the game was certainly closer than it needed to be, Washington came away with its 11th win in the past 13 games and two points that tightened its grasp on the division lead. The Capitals sit atop the Southeast with 48 points, four ahead of the Winnipeg Jets.

Saturday marked the first time that the Capitals have blown a four-goal lead since December 11, 2006, according to STATS. That time they weren’t so lucky, falling 5-4 in a shootout to Pittsburgh.

But this lost lead was the second time in a week that they gave up three third-period goals to put a game in jeopardy.

“We sat back on our heels and let them come at us and score goals and we can’t let that happen, starting with myself,” said Green, who has recorded the game-winning goal in the past two games.

“Tomorrow we’re going to wake up and we have our two points. That’s all that matters and this game’s put away but we have to learn from this,” Green said. “We can’t let situations like that happen.”

What concluded as an overtime thriller certainly didn’t begin like one. With 13:45 gone in the first, on Washington’s fourth power play of the game, Mike Ribeiro found Troy Brouwer open near the hash marks and the rangy winger blasted a slap shot past Ben Bishop for a 1-0 lead to spark an offensive outburst.

Five minutes later, the fourth line worked to put Washington up 2-0. Matt Hendricks checked Lightning defenseman Victor Hedman in the Capitals’ zone creating a turnover that sent Jay Beagle and Aaron Volpatti racing up ice on a 2-on-2. As the duo entered the zone, Beagle surveyed the scene and found defenseman Jack Hillen joining the rush. Hillen snapped the puck glove side for his second goal in three games.

Washington’s top line wasn’t about to let the opening frame expire without joining in on the fun. In the final minute of the first, Nicklas Backstrom sent an outlet pass through the neutral zone where the puck caromed off Tampa Bay forward Alex Killorn and was sent bouncing into the Lightning zone. Ovechkin was already racing up the right wing boards and found an extra, explosive gear. He beat Hedman to the puck to skate in alone, then beat an out-of-position Bishop to give the Capitals a 3-0 lead with 37.7 seconds remaining before intermission. It was a lopsided start not just on the scoreboard but in the overall play as well as Washington fired 20 shots on net and held the Lightning to six, which was as many as Ovechkin recorded in that same span.

The Post Sports Live crew discuss the Washington Capitals recent momentum and what attributed to Alex Ovechkin’s turnaround. (Post Sports Live)

“Everything went our way in the first period, and sometimes you lose a little bit of momentum because it was a little too easy, and you get a little flat,” Coach Adam Oates said. “All of a sudden here they come, and you start sinking yourselves, and before you know it, it’s happening pretty fast.”

Garon started the second period in net for Tampa Bay, but wasn’t much better. He allowed a pair of goals in the first six minutes of the stanza.

Jason Chimera scored his second goal of the year after a nice back-and-forth passing play with Mathieu Perreault to put Washington up 4-0 with 2:41 gone in the second.

Richard Panik put Tampa Bay on the board at 4-1 just over a minute later as the Capitals were caught scrambling around their own zone, but then Perreault fed Eric Fehr for an easy tip-in and a 5-1 advantage with 5:26 gone in the second.

And that was where the Capitals stopped playing the disciplined, supportive style that has helped them surge up the Eastern Conference standings and into a playoff position. Martin St. Louis scored with 1:13 remaining in the second period to cut the deficit to 5-2 and give the Lightning hope.

“Before the third period we just said stay confidence, we know they going to come out hard. We know they going to try to save the game,” Ovechkin said. “It’s good lessons right now for us. I hope for next time when we get lead like that we’re not going to stop playing and play our way.”

With 4:23 gone in the third, Panik scored on a redirection in front to cut Washington’s lead to two and less than four minutes later St. Louis followed with his second tally on a rebound to make it 5-4. Less than 12 minutes remained in regulation. Washington’s advantage rapidly disappearing — and the Lightning only grew more bold.

Teddy Purcell tied the contest at 5 on a backhander with 2:35 left in the third. In overtime, though, Marcus Johansson drove the net and drew a slashing penalty on Vincent Lecavalier for the power play opportunity that Green capitalized on.

It certainly wasn’t the way the Capitals would draw up a win, but it counts all the same.

“Sometimes when you get a big lead, the game’s really hard to play,” Hillen said. “And we didn’t do a great job of staying in it. We tried, but we didn’t do a great job. And then we got the two points in overtime, and that’s all that matters.”