The Sharks have home-ice advantage against the St. Louis Blues in the conference final and will host Game 1 of the best-of-7 series Saturday.
"It was nice. I'm not going to lie," Pavelski said. "Come out, score early, get that shot of adrenaline, which was going since the drive in to the rink. The crowd was great. ... It was fun."
[WATCH: All Avalanche vs. Sharks highlights | Complete series coverage]
Pavelski missed the first six games of the series against Colorado after sustaining a concussion in a 5-4 overtime win against the Vegas Golden Knights in Game 7 of the first round April 23.
"It really was a coin toss," San Jose coach Peter DeBoer said of Pavelski's return. "He obviously made the ultimate decision, and what an impact. What do you say? He's a special player, special guy."
Video: #ThirstForTheCup: Sharks moves on to Conference Final
Tomas Hertl and Joonas Donskoi scored, and Martin Jones made 27 saves for the Sharks.
Mikko Rantanen and Tyson Jost scored, and Philipp Grubauer made 24 saves for the Avalanche.
"Our season is over," coach Jared Bednar said. "It's tough. We set high expectations for ourselves, and we came up a little bit short. ... Our guys worked every day to try to fulfill our expectations. It was a real good series, but they were the better team for too big a portion of tonight's game, and they won, and they deserved to win."
Pavelski scored on a deflection of a shot by Brent Burns at 5:57 of the first period to give the Sharks a 1-0 lead.
"It was nice to get in there and feel some production early and just have a good start as a group," Pavelski said. "We felt like we were going. We give them one there at the end of the first, which takes a little bit away from it. But come in with the lead after the first period, that's what we wanted."
Hertl made it 2-0 at 11:35 when he scored off a pass from Pavelski from behind the net. It was his ninth goal of the Stanley Cup Playoffs, tied with teammate Logan Couture for most in the NHL.
Video: Pavelski feeds Hertl for Sharks' second goal vs. Avs
"Right away when I saw Pav, I knew the puck was coming, just easy job for me to finish there," Hertl said. "... It was a [heck] of a series. The Avalanche did such a great job, and we are for sure happy for a huge win tonight."
Rantanen scored with seven seconds left in the first to make it 2-1.
Colorado appeared to tie the game when Colin Wilson scored from the slot off a pass from Nathan MacKinnon at 7:49 of the second period. But San Jose coach Peter DeBoer challenged for offside, and video review showed Gabriel Landeskog in the zone ahead of the puck before going off for a change.
"I was just as surprised as anybody," Landeskog said of the goal being overturned. "I came off, and all of a sudden two seconds later we score. I didn't think anything of it, to be honest with you. And then we were wondering why they weren't dropping the puck.
"Obviously I was still on the ice. We saw some replays on the bench and from what we saw it could have gone either way. ...
"It's a clumsy mistake, you know. Get off the ice. ... If I could have done something different on that play, I would have jumped the boards a lot quicker."
Donskoi scored with a wraparound at 12:37 in the second to give the Sharks a 3-1 lead. It was his first goal in 40 games dating to Jan. 10.
"It's a time where we thought it was 2-2 and we kind of got caught sleeping, and it ended up being 3-1 shortly after that," Avalanche defenseman Ian Cole said. "So regardless of what happens, how that call turns out, we need to keep playing and we can't let it affect us, and I think we did."
Jost scored to make it 3-2 51 seconds into the third period.
Video: COL@SJS, Gm7: Jost beats Jones with backhander
MacKinnon sustained a right-shoulder injury when he lost his balance and fell into the boards at 1:44 of the first period. He went to the locker room at 2:18 before returning at 15:53.
"It's your best player that goes off; there's all kind of emotions and thoughts that go through your mind at that point, especially the second shift of the game," Landeskog said.
They said it
"That was huge. Me personally, I wasn't sure if he was going to play tonight. When I got to the rink, I saw him in the lineup, and he scored a huge goal right at the beginning. He's obviously a huge part of this team, and I feel like everyone got energy when we saw him back there." -- Sharks forward Joonas Donskoi on captain Joe Pavelski's return from a concussion
"I'm going to look back at it as a great season with a lot of ups and down. The way we battled the last month of the season and this playoff, I'm really proud of the group we have. We were counted out numerous times, but as a group we believed, and it was a big step for this organization." -- Avalanche captain Gabriel Landeskog
Need to know
The Sharks improved to 8-4 in Game 7 in their history, including 5-1 at home. The Avalanche are 4-7 since relocating from Quebec for the 1995-96 season, including 0-4 on the road. ... DeBoer is the second coach in NHL history to win his first four Game 7s (Tommy Ivan with Detroit Red Wings in 1949 Semifinals, 1950 Semifinals, 1950 Stanley Cup Final and 1954 Stanley Cup Final). He has won three with the Sharks after winning one with the New Jersey Devils. … Burns had 10 points (four goals, six assists) in the series.
Avalanche: Season over
Sharks: Host Game 1 of Western Conference Final against St. Louis Blues on Saturday (8 p.m. ET; NBC, CBC, SN, TVAS)
Video: Pavelski helps Sharks advance to WCF with Game 7 win