Excellent goaltending explains only part of the Avalanche’s 5-0 start behind an NHL-best 0.8 goals-against average. The newly adopted defensive-zone coverage in front of goalies Semyon Varlamov and Jean-Sebastien Giguere has been equally stellar.

“Varly and I are what people are talking about, but it’s a different team in front of us,” Giguere said Monday. “We’re on our toes, more into the game, more in the guys’ face instead of always letting the opposition come to us.”

Credit rookie NHL coach Patrick Roy for installing the Detroit-tested system in Denver. The hall of famer has kicked any evidence of zone defense at even strength out the door. Roy demands that his defenders continually move their feet and pressure the puck carrier.

“It’s man-to-man/support,” Roy said of the defensive coverage he brought with him from his eight-year stint with major junior’s Quebec Remparts. “More and more teams will have their defense men involved in the attack, and if you play (zone), you cannot follow them.

“All the teams that I’ve watched have success — St. Louis, Detroit and the other top teams — are doing it. And in order for us to have some success, there are things you have to copy, and this is one of the big things.”

Roy’s defensive system has been fine-tuned with the help of his assistants, including defensive development consultant Adam Foote, and is being taught to the club’s minor-league affiliates. Much of it is basic hockey.

“There’s a few ways to do defensive-zone coverage — every team has a different system — but if guys don’t buy into it, like what we did last year, you’re not going to have success,” Giguere said.

There is no winging it with Roy. For example, if the opponent creates a 3-on-3 rush, the Avs’ two behind-the-play forwards aren’t coasting into the defensive zone and thinking transition. Roy wants them to support and smother the attack before the opponent’s defense can get involved.

“The biggest part of our D-zone is our forwards, and a lot of what Patrick is telling us to do is support — play man-to-man and when someone gets beat, there’s always a guy supporting you,” Avs defenseman Erik Johnson said.

Colorado is allowing 34 shots per game, 26th in the league and about three more than it is producing. But that’s not necessarily a bad thing when most of the shots are from the perimeter and the goalie and his defenders are working together in unison.

“A lot from the perimeter,” Giguere said of the shots allowed. “We’ve done a great job taking rebounds away, and the D has done a good job boxing out.”

Basic defense isn’t overlooked in practice. For example, if Johnson is in front of the net with an opposing forward and his defensive partner gets beat in the corner to create a 2-on-1 chance in front of the net, Johnson does not play the puck. He plays the pass, and supports the goalie if the puck carrier goes for a jam.

“No only do you trust the goalie to make the easy stop on the sharp angle, but you’re there, in between with a good stick,” Johnson said.

Overall, Johnson said all of Roy’s demands have been well-received: “Guys are playing with more confidence because they’re allowed to play their game within the systems. We just believe in what he’s telling us to do.”

Mike Chambers: mchambers@denverpost.com or twitter.com/mikechambers

DALLAS AT COLORADO

7 p.m. Tuesday, ALT; 950 AM

Spotlight on Alex Chiasson: The rookie forward from Boston University leads the Stars with three goals and brings a four-game points streak to Denver. Chiasson, 23, has 12 points (nine goals) in his first 11 career NHL games. The Quebec native amassed seven points, including six goals, in his first seven NHL games last season.

NOTEBOOK

STARS: They have won three consecutive games against the Avs in Denver, with captain Jamie Benn leading the way with six points (two goals) in those contests. Former Edmonton captain Shawn Horcoff, 35, is having a tough start for his second NHL team, without a point and minus-2 in four games. … Dallas hosts Colorado in three of the five meetings between the new division rivals this season. … Former Boston winger Tyler Seguin is fitting in well with the Stars, leading the team with six points. … Former Nebraska Omaha goalie Dan Ellis is scheduled to start in net.

AVALANCHE: Goalie Semyon Varlamov is scheduled to start against Dallas and Thursday against Detroit. Varlamov (4-0) and backup Jean-Sebastien Giguere (1-0) were co-recipients of the NHL’s No. 2 weekly star Monday, an honor Giguere felt was deserving for Varlamov alone. … Rugged winger Cody McLeod practiced Monday, only two days after being removed from a 5-1 victory at Washington after taking a shot off the side of the knee. … The Avs are a perfect 12-for-12 on the penalty kill and a decent 21 percent (4-of-19) on the power play.

Mike Chambers, The Denver Post