CHICAGO -- Given the difficulty of their surroundings, the Dallas Stars realized just how much a quick start against the defending Stanley Cup champions could benefit them on Tuesday night.

So when the Stars tallied four first-period goals, including two in a 25-second span, the jumpstart they were hoping for fueled not only Dallas' third straight victory, but one that clinched a playoff berth.

Vernon Fiddler scored twice and the Stars built off their quick offensive start in a 6-2 victory over the Chicago Blackhawks at the United Center.

The win was the Stars' fourth in five games against Chicago this season.

"(The United Center) is one of those buildings you have to be ready to go or you're going to get it handed to you," Fiddler said. "We came over here prepared and stuck to the game plan and capitalized on our opportunities.

The Stars took a commanding first-period lead, which was fueled early by their fourth line, which produced a pair of goals in the span of less than 30 seconds. Colton Sceviour flicked a shot from behind the net that bounced off of Chicago goaltender Scott Darling before Sceviour followed up with a pinpoint pass to Fiddler to provide Dallas with the early 2-0 advantage.

Not only did the Stars jump out early like they hoped, but got production from a line that sparked Dallas throughout the playoff-clinching win.

"Anytime you can production up and down your lineup, it helps," Sceviour said. "Especially at a time of the year when games are so close and it's so hard to win."

Patrick Eaves' power-play goal extended the lead to 3-0 with just under four minutes to play in the period. Fiddler then finished off the scoring barrage when he out-raced Patrick Kane to the puck and then beat Darling on a short-handed goal following a Blackhawks' turnover for a 4-0 advantage.

Just like that, the Blackhawks -- who have lost five of their last six games -- found themselves in a rut they couldn't get out of the rest of the night.

"It was hard to watch," Blackhawks coach Joel Quenneville said. "I don't know if it's confidence, but we have to find a way to rectify the way we play and the way we play with more urgency."

The Stars had plenty of that.

Dallas chased Darling after registering four goals on its first 15 shots and carried a 5-1 lead into the third period after Radek Faksa padded an already comfortable lead late in the second period when he fired a shot past Michael Leighton. Darling, who was pulled, giving way to a goalie who hadn't appeared in an NHL game since 2013.

Faksa's goal swung the momentum back to Dallas after the Blackhawks had cut the deficit to 4-1 with 3:37 left in the second period. Chicago's Andrew Shaw redirected a shot out of the air and past Stars goalie Kari Lehtonen, who had stopped the first 18 shots he faced before Shaw's goal.

Lehtonen, who finished with 30 saves, surrendered up a second goal midway through the third period when the Blackhawks' Richard Panik was able to slip the puck under his left pad to make it 5-2.

But Dallas' Cody Eakin responded again and capped the scoring with an empty-net goal late in the third period, which punctuated the Stars' entry into the Stanley Cup playoffs.

"The last few years, we've been that team that is fighting for (the playoffs) right up until the last few games," Fiddler said. "Obviously it's nice to get the 'X' next to Dallas, but obviously, we know we've still got lots of work ahead of us."

NOTES: Stars D Jordie Benn returned to the lineup after missing eight games with a lower-body injury. ... D Kris Russell was a game-time scratch with a lower-body injury. Russell skated in the morning to test his strength. D Jamie Oleksiask and LW Travis Moen were also scratches for the Stars. ... Blackhawks G Corey Crawford missed his third straight game with an upper-body injury. Coach Joel Quenneville responded with a "we'll see" when asked if Crawford would travel for Chicago's upcoming four-game road trip that begins Saturday in Calgary. Crawford's replacement, Scott Darling, made his fourth straight start for the first time since December. ... Quenneville said F Marcus Kruger could play Saturday against the Flames. Kruger has been out since Dec. 18 after undergoing surgery for a dislocated wrist. ... C Dennis Rasmussen, D Christian Ehrhoff and LW Brandon Mashinter were scratches for Chicago.