The Vegas Golden Knights (7-3-3) led 2-0 after the first period but gave up six goals in the final 40 minutes of action, falling 6-3 to the Tampa Bay Lightning (7-5-2) Thursday night at T-Mobile Arena.

Ivan Barbashev scored twice, and Mitch Marner had three points, but it wasn’t enough to get the best of the visiting Lightning, who completed the sweep of the season series.

First period

The first two periods were very similar, with both teams dominating one of them.

The Golden Knights had arguably their best opening 20 minutes of the season, outshooting Tampa Bay 15-3 and taking a 2-0 lead into the first intermission.

Both goals came courtesy of Barbashev, with Marner assisting both.

Barbashev opened the scoring 7:25 into the contest with his fifth tally of the season. Noah Hanifin recorded the primary assist on the play for his first point of the year in his third game (and second since returning from an injury that kept him out of the lineup for 10 games).

Barbashev doubled Vegas’ lead at 15:53 off a great centering feed from Marner, finding open ice in the slot to beat Andrei Vasilevskiy.

Second period

However, the Lightning stole the Golden Knights’ playbook in the second period, holding a 15-4 edge in shots and a 2-0 advantage in goals to even things up through 40 minutes. Both goals came courtesy of Tampa Bay’s third line.

The first came just 36 seconds into the period, as Gage Goncalves made a strong play to take advantage of a Hanifin turnover.

Less than three minutes later, the Lightning’s third line struck again, as Dominic James scored the first goal of his NHL career. Carl Lindbom made the save on the initial attempt but fumbled the rebound; an unfortunate bounce left the puck sitting in front of a wide-open cage, and James buried it to reset the score.

Third period

The two clubs combined for three goals in the span of just 1:24 early in the third period.

First, Nikita Kucherov gave Tampa Bay its first lead of the game when he scored just after a Lightning power play expired, making it 3-2 just 2:48 into the final frame.

The Golden Knights responded less than a minute later when a Marner shot deflected off defenseman Victor Hedman on its way into the back of the net, making it a 3-3 game at 3:37.

However, the see-saw stretch continued, and Brandon Hagel put Tampa Bay back on top just 35 seconds later.

Vasilevskiy took a double-minor for high-sticking Reilly Smith, but the Vegas power play was unable to convert. The Golden Knights’ best chances came on the shift after the power play expired, but Vasilevskiy stood tall to keep it a 4-3 game.

With under six minutes left in the period, the Lightning went back on the power play. The Golden Knights’ penalty kill has been excellent, and while Tampa Bay has been uncharacteristically quiet on the man-advantage this year, Vegas tempted fate one too many times. A Kucherov one-timer from the right circle gave the Lightning a two-goal lead with 5:47 left.

The Golden Knights got yet another power play but couldn’t cut the deficit. Hagel scored an empty-netter to seal the 6-3 win for the Lightning.

The power play continues to be a thorn in Vegas’ side, and tonight was no exception.

The Golden Knights went 0-for-3 in the third period, wasting a four-minute opportunity after Tampa Bay went up 4-3. Putting Hanifin on the top unit is worth exploring at this point, but Vegas has to find some answers with Mark Stone still labeled as week-to-week.

Though they had an incredible start to the game, the Golden Knights completely disappeared in the second period. Up 2-0, the Golden Knights needed to come out and continue to control the game. That didn’t happen. Tampa Bay is a deep team, and giving up two quick goals to the Lightning’s bottom six turned the tide of the game.

Even so, this was a 2-2 game going into the third period. However, Vegas was outscored 4-1 in the final 20 minutes.

Unlike the Lightning, the Golden Knights did not get contributions from their depth players, which is another pattern that needs to be addressed moving forward.

Lindbom struggled in his third career start, stopping 21 of 26 shots for an .808 save percentage. He was out of position frequently and was unable to slow things down in a wild third period.

One positive takeaway from the loss was the play of the new-look top line of Barbashev, Marner and Jack Eichel. They accounted for all three of the Golden Knights’ goals and finished the contest with a 19-16 edge in Corsi and a 14-4 lead in shots.

The Golden Knights are 1-2-0 through three games of this six-game homestand, which continues Saturday against the red-hot Anaheim Ducks.

Statistics courtesy of Natural Stat Trick.