NEW YORK -- Vernon Wells had one thing on his mind in the fifth inning.
"I don't want to make an out," Wells said. "Everyone else is doing something."
Wells had nothing to worry about. He got to join in the fun, too.
Russ Adams added a two-run double in the inning, when the Blue Jays scored eight times off Mussina in their biggest inning since a nine-run sixth against the Angels on June 15, 1999, according to the Elias Sports Bureau. They had seven hits off Mussina and Felix Rodriguez, and 10 consecutive batters reached with one out.
"We had some good at-bats," Blue Jays manager John Gibbons said. "We were way overdue anyway."
Mussina (12-8) hurt himself by allowing two walks and hitting a batter. He allowed eight runs in an inning for the first time since Sept. 24, 2003, against the Chicago White Sox, according to Elias.
Dave Bush (3-7) allowed five hits in six scoreless innings to win for the first time since Aug. 3. He beat the Yankees for the first time since pitching a career-best two-hitter against them in a 7-0 victory in Toronto on Oct. 1.
"He always pitches very good when he's facing these guys, which is tough to do," Gibbons said.
Hideki Matsui had three hits and drove in two runs for the Yankees, and Bernie Williams added a three-run homer off Vinnie Chulk in the ninth, his first career pinch-hit homer.
The Yankees had their six-game home winning streak snapped and fell into a tie with Oakland for the AL wild-card lead.
"Just when you think you have everything rolling in your direction, and then something that doesn't figure happens," Yankees manager Joe Torre said. "That's what happened tonight."
Mussina had retired 11 straight batters after striking out Shea Hillenbrand to open the fifth. But he walked Corey Koskie and allowed singles to Gregg Zaun and Reed Johnson to load the bases, then lost control of the plate.
Eric Hinske was hit on the hand and Mussina walked Orlando Hudson to force in another run. Adams doubled to right to make it 4-0, and Hudson scored on Frank Catalanotto's single. Wells drove Mussina's next -- and last -- pitch over the left-field fence for his 24th homer and an 8-0 lead.
Hillenbrand doubled off Rodriguez and scored on Koskie's single to cap the inning. The Yankee Stadium crowd of 54,705 let out a huge roar when Zaun flied to center for the second out.
Mussina didn't think he was pitching well, even when he seemed to get the Blue Jays out with ease in the early innings.
"It wasn't great stuff. I was just really fortunate getting people out," Mussina said. "I didn't warm up well, it just felt like one of those days when I was going to struggle.
"I was doing a better job of guessing where they were going to swing than they were guessing where I was going to throw. But it wasn't really great stuff."
Bush allowed a leadoff double to Alex Rodriguez in the fourth, but came back to strike out Jason Giambi, Tino Martinez and Jorge Posada in succession. Bush had a season-high seven strikeouts, but couldn't explain the reasons for his success against the Yankees.
"I don't think it's anything in particular," he said. "I've been hit around by them a little bit, too.