Rodrigues then gave the Avalanche a 3-2 lead at 3:01 of the third period, beating Rittich blocker side with a wrist shot through the legs of Dillon from just inside the blue line.
"I was just trying to put it to the net. Wasn't even looking at the net," Rodrigues said. "The guy was in front of me. I just tried to shoot it through his legs and catch the goalie off guard, and it worked out."
Lehkonen scored into an empty net at 18:31 for the 4-2 final.
Avalanche forward Andrew Cogliano left the game in the first period with an upper-body injury. Malgin left in the third period with an undisclosed injury.
"Cogliano is out, upper body. No timetable yet. Malgin [will] probably miss tomorrow, too. No timetable," Colorado coach Jared Bednar said. "Every time someone gets hurt, there's concern that it could be serious or longer than what it takes, but we just have to keep moving on, moving forward. Hopefully we'll get good information over the next couple of days on both of them."
NOTES:Rantanen's 55 goals are tied for third in Avalanche/Quebec Nordiques history. Michel Goulet, who scored 55 goals with the Nordiques in 1984-85, also scored 56 in 1983-84, and 57 in 1982-83. … Colorado won at least 50 games in back-to-back seasons for the first time in its history. … Lehkonen returned to the lineup after missing 15 games because of a broken finger. … Rittich was making his first start since March 14. ... Prior to the game, it was announced that Avalanche captain Gabriel Landeskog, who has not played this season because of knee surgery, would not return for the playoffs.