Roy posted his 17th career playoff shutout to extend his own record and the Avalanche moved within one win of their third straight Western Conference finals appearance with a 3-0 blanking of the Los Angeles Kings.
Roy entered with a .899 save percentage, which was among the worst of the goaltenders still active in the postseason. But he singlehandedly kept the game scoreless in a lopsided first period and went on to record his second shutout of the conference semifinals.
"Tonight, Patrick was the difference. If it weren't for Patrick, we could be in a totally, totally different setup," Avalanche coach Bob Hartley said.
Alex Tanguay, Milan Hejduk and Chris Drury also scored second-period goals for the Avalanche, who were without injured captain Joe Sakic but grabbed a commanding three games to one lead in the best-of-seven series. They can eliminate the Kings at home on Friday night.
"It's going to be important to play a good game because they showed us tonight, especially in the first (period), that they are not going to look down and they are going to keep working hard," Roy said. "We're going to have to go and get it if we want to win."
In Game Four of the conference quarterfinals against Detroit, Los Angeles rallied from a three-goal deficit in the final 6:07 of regulation before winning in overtime. There was no comeback on Wednesday as the Kings managed just five shots in the third period, none after pulling goaltender Felix Potvin with 3 1/2 minutes remaining.
"We're not far, but we are not close enough," Los Angeles coach Andy Murray said. "We've just got players that have to play better for us. We played pretty hard in the first period and had great chances. We didn't score, so somebody didn't shoot the puck hard enough."
The Kings had three of the four power plays in the first period and outshot the Avalanche, 10-3. But Roy made early stops on Adam Deadmarsh and Ziggy Palffy, who have combined for just a goal and two assists in this series after netting 11 points against Detroit.
The game turned early in the second period. In the opening minute, Tanguay was hit in the throat by a clearing attempt by Los Angeles defenseman Aaron Miller.
On his next shift, Tanguay tried to throw a pass across the goalmouth to former King Rob Blake, but the puck deflected off Los Angeles defenseman Jere Karalahti and slid past goaltender Felix Potvin.
"Rob Blake was wide-open on the other side. I was trying to pass, luckily it went in," said Tanguay, who has six points in this series but had not scored a goal since Game Four of the conference quarterfinals against Vancouver.
Colorado had both power plays in the second period and converted at 16:27 with three seconds left on Mathieu Schneider's holding penalty. Jon Klemm, who scored the game-winner on Monday, took a slap shot from above the right faceoff circle that Hejduk deflected past Potvin for his third playoff goal and second in as many games.
"After the second goal, the Kings opened it up. Scoring that second goal was the key to this game because it made the Kings open things up," Roy said.
Drury scored his league-leading sixth playoff goal less than two minutes later to make it 3-0. He stripped the puck from Jozef Stumpel in the neutral zone, raced in alone on Potvin and flipped a wrist shot over his glove.
Potvin made 18 saves but could not prevent the Kings from suffering their third straight loss after winning the series opener in overtime.
"We had a real strong first period and didn't follow that up. In the second period, the same way," Potvin said. "You can't do that against good teams like Colorado. You've got to play strong for three periods."