LAS VEGAS -- Jonathan Marchessault scored his first hat trick with the Vegas Golden Knights in a 7-3 victory against the Pittsburgh Penguins at T-Mobile Arena on Saturday.
Marchessault put Vegas ahead 4-3 at 12:26 of the second period and scored 3:50 later for a 5-3 lead. He completed his second NHL hat trick when he scored into an empty net with 21 seconds remaining in the third for the 7-3 final. He had one goal in his previous 11 games.
"It's definitely hard sometimes trying to make the right plays at the right time," Marchessault said. "It's the way it goes sometimes. You just have to battle through it. I was happy to get rewarded."
[WATCH: All Penguins vs. Golden Knights highlights]
Shea Theodore, Max Pacioretty, Oscar Lindberg and William Karlsson scored for the Golden Knights (29-17-4), who won for the ninth time in 11 games. Marc-Andre Fleury made 34 saves and had an assist on Marchessault's third goal.
Fleury is 2-1-0 against his former team. He played 13 seasons for the Penguins before the Golden Knights selected him in the 2017 NHL Expansion Draft.
"I wanted to do well, obviously," Fleury said. "I want to win any given night, but it feels weird when you play against coaches and players that I've played with."
Video: PIT@VGK: Golden Knights strike twice in 43 seconds
Phil Kessel, Dominik Simon and Sidney Crosby scored for the Penguins (26-16-6), who lost for the third time in four games after winning 10 of their previous 11. Casey DeSmith made 28 saves.
"We gave up three breakaways and two 2-on-1s in the first 20 minutes of the game," Pittsburgh coach Mike Sullivan said. "We just didn't play the game smart."
Kessel scored his 20th goal of the season at 3:51 of the first period to give the Penguins a 1-0 lead.
Vegas scored three straight goals in a stretch of 9:54. Theodore scored on the power play at 6:09 to tie it 1-1, Pacioretty scored at 15:20 for a 2-1 lead, and Lindberg scored 43 seconds later to make it 3-1.
"We just made some mistakes, and early is probably when we made the most mistakes," Crosby said. "We found a way to get back in in the second. I thought we did a lot of good things."
Simon scored 16 seconds into the second period to cut the lead to 3-2. Crosby scored his first goal against the Golden Knights at 5:56 to tie it 3-3.
Evgeni Malkin appeared to give the Penguins a 4-3 lead at 10:17, but the goal was waved off after video review showed Malkin kicked the puck into the net.
Marchessault scored his first goal 2:09 later to give Vegas the lead.
"It was a big goal," Marchessault said. "We let them back in the game and that's not what we do normally. Their top players, you give them enough room and they'll make you pay."
Karlsson scored at 13:45 of the third period to make it 6-3. He had an assist on Marchessault's second goal for his first point in nine games.
"They've been pressing for goals for the last little while, and to see [Marchessault] get three tonight and for Karlsson to get one, that's huge for our club," Golden Knights coach Gerard Gallant said. "They've played really good hockey and they played really good defensive hockey … but when those guys are scoring and we get everybody else scoring and chipping in it's going to be big for our team."
Video: Enterprise Hat Trick: Marchessault nets three
They said it
"I think it'll be good for all of us to get away for a bit. When we get back, we have to be focused and determined on playing our best hockey. The most important thing from my standpoint … we have to find a way to become a team that has a clear identity on what it is and how we're going to play, and everyone has to buy into it." -- Penguins coach Mike Sullivan on not playing again until Jan. 28
"Tonight was definitely special. When we play Pittsburgh, it's always special for us because it's the best player on our team playing against his old team. We definitely wanted to show up for him." -- Golden Knights forward Jonathan Marchessault on goalie Marc-Andre Fleury
Need to know
Marchessault's first NHL hat trick was March 25, 2017, as a member of the Florida Panthers. Karlsson (twice) is the only other Golden Knights player with a hat trick. … Vegas defenseman Colin Miller had two assists in his return after missing 13 games with an upper-body injury. … Vegas forward Brandon Pirri had his six-game point streak end. … The Golden Knights were 1-for-30 on the power play in the previous 10 games before Theodore's goal. … Penguins forward Patric Hornqvist played 16:59 and was minus-2 in his first game since sustaining a concussion Jan. 8. He missed four games. … Kessel has 11 straight seasons of at least 20 goals. Only Patrick Kane and Keith Tkachuk, with 12 seasons each, have a longer streak among U.S.-born players.
Penguins: Host the New Jersey Devils on Jan. 28 (7 p.m. ET; SN, ATTSN-PT, MSG+, NHL.TV)
Golden Knights: Host the Minnesota Wild on Monday (6 p.m. ET; ATTSN-RM, FS-N, FS-WI, NHL.TV)
Video: Marchessault's hat trick powers Golden Knights to win