Anderson hit a grand slam and a three-run homer as part of a four-hit, 10-RBI night, serving as the Angels' most damaging offensive performer. The home team called it a historic night, scoring its highest total of runs in a game against the Yankees, while Mussina simply called it "awful."
"It's tough to take," Mussina said. "I think that was in the top-five worst games of my career, right there. When you can't throw strikes, it really hurts. When I was throwing strikes, they were hitting them."
The Yankees fell six games behind the Red Sox in the American League East and lost a game on the Mariners in the AL Wild Card pursuit, falling 2 1/2 back of Seattle.
Mussina endured his shortest career start as a Yankee, battered for seven runs in 1 2/3 innings, his quickest hook since 1995. The early exit forced him to watch from the clubhouse for most of the fireworks -- quite literally, as the California night sky was illuminated by red sparks shooting from beyond the center-field rock pile.
"It never looked like he got into a rhythm," said Yankees manager Joe Torre. "It was the same story. He's such a touch-and-feel guy that when he can't put the ball where he wants to, he gets frustrated by it. That's what I saw."
Anderson's two-run double in the first brought home the Angels' first runs and put him on his way to coming within one RBI of the American League record of 11 in one game, set by the Yankees' Tony Lazzeri in 1936.
Mussina faced eight batters in the second, allowing five runs on five hits in that inning before handing the ball off to reliever Ron Villone.
After a string of four consecutive victories, Mussina has now been hit hard in his last two starts. He was looking to rebound from a season-high seven runs allowed in an Aug. 16 loss to the Tigers and said he felt good in his pregame bullpen session on Tuesday, though obviously the results were anything but acceptable.
"I try not to get too caught up in believing things are going to be one way and that they're going to stay that way for a long time," Mussina said. "This game isn't like that. We all go on hot streaks and we go on bad streaks. Just because you're going good for a while doesn't make the bad times any better."
Asked about the possibility of an injury hampering his performance, Mussina said that there is nothing wrong with him except that he was unable to throw the ball where he wanted.
Likewise, Torre dismissed the idea that Mussina may be masking something, saying, "There's nothing that I know is physically wrong with him."
"Hopefully, there isn't anything wrong," Torre said. "Obviously, with the last couple of starts, I know he concerns himself with it. We certainly do."
The Yankees briefly surged to make the game closer, putting up four runs in the third inning against Angels right-hander Kelvim Escobar.
"We're not going to stop playing," Torre said. "It's just that what we do is going to be based on how we pitch. Tonight, we didn't pitch well."
The Angels greeted Villone rudely when he opened the fourth, as the left-hander did not retire a batter and had to be relieved after allowing a bases-loaded walk to Chone Figgins, accounting for one of four runs Villone was charged with.
"It was the beginning of an ugly night," Villone said. "It could have been stopped if I'd come back and had a good inning. It's ultimately just a bad start to the possibility of us getting back on top."
Edwar Ramirez, twice released by the Angels organization in 2003 and 2005, made his first Anaheim appearance against his old club and surrendered a three-run homer to Anderson in a two-inning appearance, though one of the runs was charged to Villone.
Sean Henn, who was originally thought to be unavailable due to numerous warmup sessions in Monday's loss, volunteered for three innings of relief duty and allowed five runs, including a grand slam to Anderson that drew a curtain call for the Angels outfielder in the sixth.
Henn's performance may have staved off a possible roster move for the Yankees, who could have been left short-handed in the bullpen for Wednesday's series finale. Luis Vizcaino threw 17 pitches in the eighth, and the Yankees were able to keep rookie Joba Chamberlain out of action.
"[Henn] took a bullet for us today," Torre said.
Alex Rodriguez's 41st and 42nd home runs, solo shots off Escobar in the second inning and off Marc Gwyn in the ninth, were reduced to footnotes by the blowout final. Escobar went six innings for the victory, allowing five runs and striking out seven.
Wilson Betemit hit a three-run homer and Bobby Abreu drove in two runs for the Yankees, who have lost six of their eight games against the Angels this season.
Bryan Hoch is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.