DENVER -- Wyatt Johnston scored twice on the eve of his birthday as the Dallas Stars pushed Colorado to the brink of elimination Monday night with a 5-1 victory.

Johnston had shorthanded and power-play goals for the Stars, who grabbed a 3-1 lead in the second-round, best-of-seven series. Dallas can close it out at home in Game 5 on Wednesday.

Miro Heiskanen and Evgenii Dadonov also scored, while Sam Steel added a late empty-net goal. Jake Oettinger made 24 saves.

"[Johnston] came out possessed tonight," Stars coach Peter DeBoer said. "He was all over the rink. Just fantastic, fantastic young hockey player that's going to be a cornerstone."

About an hour before the game, the National Hockey League and National Hockey League Players' Association announced that Colorado's Valeri Nichushkin was suspended for at least six months without pay. He was placed in stage 3 of the league's player assistance program. It's the second time this season Nichushkin has been in the program.

A Colorado lineup missing Nichushkin, the team's leading goal scorer (nine) in this playoff run, struggled early to get on track and was outshot by a 16-2 margin in the first period. Casey Mittelstadt scored Colorado's lone goal.

"We talked about [how] we'd been the best road team all year because regardless of the building or the lineup for the other team, who's in, who's out, we approach the game the same way," DeBoer said, "and [we] took care of business."

Colorado's defense was unable to prevent Johnston and the Stars from building a 3-0 lead in the second period, and because of the hot start in the first, Dallas maintained its streak of not trailing in regulation at any point during the series. The Stars have outscored the Avalanche 6-0 in the opening periods alone.

Johnston, who turns 21 on Tuesday, scored his 10th and 11th career playoff goals. He became the eighth player in NHL history to reach double-digit postseason goals at age 20 or younger, according to league research. After the win, he was presented a candy-bar cake with a candle.

"It's been a crazy, crazy couple of years," Johnston said. "I'm just really thankful and just so happy to have met some amazing people on the way and just have a chance to be with the Stars."

Johnston took advantage of a Cale Makar turnover late in the first period and scored a shorthanded goal to give the Stars a 1-0 lead. It's the second shorthanded goal of the series for Dallas.

"That was our worst game of the series," Colorado coach Jared Bednar said after the loss, adding that it "atrocious."

It wasn't all good news for the road team, though. The Stars saw forward Roope Hintz leave the game after suffering an upper-body injury in the opening period. In his postgame news conference, DeBoer said he'd have more injury information on Hintz on Tuesday.

Since dropping the first two games of their round one series vs. the Vegas Golden Knights, the Stars have gone 7-2 against the past two Stanley Cup champions.

"We've played a lot of good hockey and put ourselves in some good positions," Stars forward Joe Pavelski said. "It's just a commitment to doing it the right way. That's number one for us."

The Associated Press contributed to this report.