EDMONTON -- The Vegas Golden Knights moved three points ahead in the Pacific Division when Shea Theodore scored at 2:13 of overtime for a 3-2 win against the Edmonton Oilers at Rogers Place on Monday.
Jonathan Marchessault had a goal and an assist, and Marc-Andre Fleury made 22 saves for Vegas (39-24-8), which also won 5-3 at the Calgary Flames on Sunday.
Marchessault tied the game 2-2 at 11:57 of the third period when he converted a centering pass form Reilly Smith, and Theodore won it with a one-timer from the high slot.
"It was a great play by [Marchessault]," said Theodore, who also scored the game-winner Sunday. "It was one of those plays where their guy kind of left the zone a little bit, and I kind of had to stay in between to see whether they were going to get it down or not. But he made a great play, and sometimes you just have to keep getting it to the net.
"When you can load up for a one-timer coming down the slot, you're just trying to get all of it, and it was just a great pass."
[WATCH: All Golden Knights vs. Oilers highlights]
Mikko Koskinen made 45 saves for Edmonton (37-24-9), which played without center Connor McDavid because of an illness.
The Oilers, who are 4-1-1 in their past six games, moved four points ahead of the Flames for second in the Pacific.
"We've been able to get points because of our two goalies (Koskinen and Mike Smith), but going down the stretch, you can't rely on them to make 40 or 50 saves a night," Edmonton forward Alex Chiasson said. "There's a disconnection in our game right now. There was a stretch where we were all five guys going up the ice, then another five breaking out together, forechecking together. Now we're reading to see what one guy's going to do, then reacting."
Chiasson gave the Oilers a 1-0 lead 9:00 of the first period when he redirected a point shot from Oscar Klefbom.
Video: VGK@EDM: Chiasson deflects Klefbom's shot for goal
Vegas outshot Edmonton 15-3 in the first period and held a 30-14 edge after the second.
"We are just not playing very well as a group right now," Oilers coach Dave Tippett said. "I thought we had addressed some things this morning, but our execution is so poor in a lot of different situations. Some of that is pure not getting the play made, and some is guys on their own page, going to their own spots and thinking that they can vary from the game plan."
Nicolas Roy tied it 1-1 on the power play at 16:58 of the second, but Ryan Nugent-Hopkins gave the Oilers a 2-1 lead at 6:46 of the third.
Video: VGK@EDM: Nugent-Hopkins fires quick shot past Fleury
The Golden Knights had 16 shots on goal in the third period.
"A gutsy effort, three [games] in four nights, playing [Sunday] night and then back-to-back," Vegas coach Peter DeBoer said. "I thought our guys showed up and really did a good job, every guy out there that dressed, goalie on out. We needed that kind of effort tonight to win in here. We knew that our attention to detail had to be good, and it was."
Video: EA Sports Overtime Winner: Theodore wins it for Vegas
They said it
"It's huge. We're getting down to crunch time here and everyone is jockeying for positions and playoffs and the standings. We knew this was going to be a big trip for us, and obviously we weren't too happy with the start of it (4-0 loss at the Winnipeg Jets on Friday), but between [Sunday] night and tonight, we're happy to get the win." -- Golden Knights defenseman Alec Martinez
"We're just a team that believes a lot in ourselves. We know if we work hard and play well, we're mostly going to get the win at the end of the night. We're a resilient team and we believe in that, and that's just the way we played for three periods." -- Golden Knights forward Jonathan Marchessault
"It's something that we have to fix right away. We went through a little stretch like this in December and we were able to get ourselves out of it. Obviously without the goaltending that we've had in the last little while, it'd probably be a different story. But we're in a good spot. We've found ways to get out of playing like this before, so we have to find a way to do that." -- Oilers forward Ryan Nugent-Hopkins
Need to know
Theodore is the second defenseman this season to score a game-winning goal in consecutive days (John Carlson of the Washington Capitals on Dec. 3 and 4). … Vegas is 11-2-0 in its past 13 games. … Nugent-Hopkins extended his point streak to six games (four goals, seven assists). … McDavid has missed seven games this season; he was out for six with a quad injury from Feb. 8 to Feb. 21.
Golden Knights: At the Minnesota Wild on Thursday (8 p.m. ET; FS-N, FS-WI, ATTSN-RM, NHL.TV)
Oilers: Host the Winnipeg Jets on Wednesday (9 p.m. ET; SN, TVAS, NHL.TV)
Video: Theodore scores OT winner, Golden Knights top Oilers