Rantanen missed the previous 16 games with a lower-body injury he sustained Oct. 21 against the St. Louis Blues. He didn't play in the third period or address the media after the game.
"Yeah, he's fine," Avalanche coach Jared Bednar said. "He tweaked his leg a little bit a couple of times and started to get a little tired, so I didn't see a reason to bring him out for the third in a 7-2 game. He'll be ready to go."
[WATCH: All Blackhawks vs. Avalanche Highlights]
Nathan MacKinnon had a goal and two assists, Nazem Kadri had two goals and Philipp Grubauer made 26 saves for the Avalanche (16-8-2), who have won three straight games.
The Donskoi-MacKinnon-Rantanen line combined for four goals, seven assists and 10 shots.
"Mikko's amazing, he makes everyone on the ice so much better," MacKinnon said. "He's one of the best players in the world. He's so young still (23), he's going to get so much better. It's fun having him back out there."
Chicago forward Patrick Kane extended his point streak to 15 games with a 5-on-3 power-play goal at 14:38 of the third period. He has 24 points (11 goals, 13 assists) in the streak, the longest in the NHL this season.
Video: CHI@COL: Kane pots PPG to extend point streak to 15
Robin Lehner allowed five goals on 14 shots before he was replaced in the second period by Corey Crawford, who made 13 saves for the Blackhawks (10-11-5), who are 1-4-1 in their past six games.
"It's embarrassing, we have to wake up, we have to turn it around," Lehner said. "It's just time to look ourselves in the mirror and do the right thing, it's what it's all about. It's on us as players to do the right thing."
Chicago took a 1-0 lead at 1:37 of the first period on Brandon Saad's shorthanded goal.
The Avalanche tied it 1-1 on Kadri's power-play goal at 7:53. Rantanen passed from the left corner to Kadri in front for a shot glove side.
Video: CHI@COL: Rantanen, Kadri connect for power-play goal
Kadri made it 2-1 at 9:18 skating down the slot after a pass from Matt Nieto.
The Avalanche increased the lead to 3-1 on MacKinnon's goal at 11:08. Rantanen passed from the side of the net to MacKinnon between the circles.
The Blackhawks had a 5-on-3 power play for 58 seconds near the end of the first period but didn't take advantage.
"Huge momentum swing there," Kane said. "It could have been huge to get us back into it."
Instead, Donskoi scored for a 4-1 lead at 2:52 of the second period. Ian Cole passed to Ryan Graves, who left the penalty box after the Avalanche killed his double-minor for high sticking. Graves fed Donskoi moving down the slot.
Rantanen made it 5-1 at 5:50, converting the rebound of Samuel Girard's shot.
Video: CHI@COL: Rantanen puts home rebound to increase lead
Donskoi made it 6-1 at 8:28, skating down the middle to convert MacKinnon's pass from the right circle, and Tyson Jost moved down left wing to score at 10:38 for a 7-1 advantage.
"It was a lot of fun," Donskoi said. "Nate and Mikko … I'm just trying to keep up with those guys, trying to grind and work hard. Those are two elite players, so it was a lot of fun. We were able to score with the chances we got."
Chicago's Dominik Kubalik made it 7-2 at 11:14.
"Very disappointed, obviously, the second period in particular," Blackhawks coach Jeremy Colliton said. "As a group we got to commit to doing it every single shift. Not every shift is going to be perfect, but the intentions have to be perfect and I don't think we can say that."
They said it
"We're just going to take these games and learn from them, try to forget them as much as possible. But these are the games that we can remember late in the season where we fought some adversity. We have to come back strong next game and get a win." -- Blackhawks forward Alex DeBrincat
"He's an elite player, he really is. The way he thinks the game, the way he maneuvers around the ice, his skill, ability, size, strength, all that, so you know he's going to be able to produce. It's just the type of player he's become. He's got pretty good linemates, too, and they had a night." -- Avalanche coach Jared Bednar on Mikko Rantanen
Need to know
MacKinnon established an Avalanche/Quebec Nordiques record for most points in November, eclipsing the previous high of 24 last achieved by Quebec's Walt Poddubny in 1988 (11 goals, 13 assists in 14 games). MacKinnon's 25 points are the most by a Colorado player in any month since Joe Sakic had 26 (15 goals, 11 assists) in 13 games in March 2000. MacKinnon has 16 points (six goals, 10 assists) in a seven-game point streak. … Saad has 11 points (five goals, six assists) in his past 13 games.
Blackhawks: Host the St. Louis Blues on Monday (8:30 p.m. ET; NHL Network, NBCSCH, FS-MW, NHL.TV)
Avalanche: At the Toronto Maple Leafs on Wednesday (7 p.m. ET; SN, SN360, TVAS, ALT, NHL.TV)
Video: Donskoi, Rantanen fuel Avs' 7-3 win vs. Blackhawks