LAS VEGAS -- The Vegas Golden Knights weren't satisfied to be the greatest expansion team in NHL history. As proud as they were of the records they set and the impact they made in their inaugural season of 2017-18, they were disappointed to come so close to the Stanley Cup and not win it.

"One thing I know," forward Jonathan Marchessault said as the Washington Capitals paraded the Cup around the ice after Game 5 of the Final at T-Mobile Arena on June 7. "We'll be back."

General manager George McPhee entered the Golden Knights' offseason saying his goal was "to make them better and to deliver the Stanley Cup." Marchessault entered training camp this season saying they had "unfinished business."

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Now they're back in the playoffs, opening the Western Conference First Round against the San Jose Sharks at SAP Center on Wednesday (10:30 p.m. ET; NBCSN, SN, TVAS) with a better roster and a chance to finish what they started.

"We're capable of anything," forward Max Pacioretty said. "We know the sky's the limit. We have everything you can ask for on a team."

The regular season wasn't as magical as 2017-18 for Vegas for a number of reasons, most notably injuries and regression. The Golden Knights (43-32-7) finished third in the Pacific Division, not first; 16th in the NHL, not fifth; 13th in goals per game (3.00), not fifth (3.27).

The Golden Knights signed center Paul Stastny as an unrestricted free agent July 1 and acquired Pacioretty from the Montreal Canadiens on Sept. 9. Stastny played three games before missing 30 with an injury. Pacioretty was in and out of the lineup with injuries, missing 13 games.

Meanwhile, the top line of Marchessault, center William Karlsson and forward Reilly Smith wasn't producing like it did last season.

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Then Vegas acquired forward Mark Stone from the Ottawa Senators on Feb. 25.

The Golden Knights were in a 3-9-1 funk before the Stone trade; they went on a 10-1-1 run afterward.

Everything clicked throughout the lineup. Like last season, they use their speed and depth to their advantage, rolling four lines and three defense pairs, only now their rebuilt second line of Pacioretty, Stastny and Stone is stronger at both ends of the ice.

"Everyone plays the same way, plays that really attacking, aggressive (style)," said Stastny, who played against the Golden Knights with the Winnipeg Jets last year, losing to them in five games in the Western Conference Final. "We come at you wave after wave.

"It all starts with our forecheck. It all starts with our skating. And all of a sudden it lets our [defensemen] be a little more aggressive, because they can trust the forwards getting back. And then once we get that puck, our first goal is just to get it right back in the zone and start attacking that net."

The Golden Knights finished the season 1-5-2. But they were locked into third in the Pacific and dealing with injuries again, and now they're entering the playoffs mostly healthy.

Goalie Marc-Andre Fleury missed nine games before returning in a 4-1 loss to the Arizona Coyotes at T-Mobile Arena on Thursday, but it gave him a chance to rest after starting 59 of Vegas' first 71 games.

Fleury could be the Golden Knights' biggest advantage. Through three rounds last season, he was 12-3 with a 1.68 goals-against average, .947 save percentage and four shutouts.

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"I think we've showed to ourselves this year, when we play the way we can, how good, how smothering, we can be on the ice," Fleury said. "When everybody contributes to the defensive part of the game, we do well. We don't give the other team much, and because of that we get chances, and we've got guys that can score.

"We added some good veterans on the team, and everybody's a little bit more experienced than last year. We know what to expect, right?"

One takeaway from last year: Don't look ahead to the end goal.

"I think there's some really good teams that have a chance, and teams have got to go through each other in order to get there," defenseman Nate Schmidt said. "You can't get too caught up in it, I think. That was one thing we were extremely good at last year, is not getting too caught up in how far we're going to get, what we're going to do.

"We have a very tough first series, and that's where you start. I think if you start looking, 'Oh, we could …' or, 'If this happens …' it gets your mind in a tizzy. You don't really focus on what you actually have to do."

When you have unfinished business, be businesslike.

"We have higher expectations, but who cares about expectations?" Marchessault said. "I don't think it's a big factor. I think it's just, you do you. We worry about us, and we just go along one game at a time."