The White Sox have lost seven of 11 and their AL Central lead was cut to 1½ games over second-place Minnesota, which rallied to win 11-8 at Tampa Bay.
"We don't have anything going forward right now," White Sox manager Ozzie Guillen said. "We can't play like that. It's going to be tough for us to compete."
Guillen noted before the game that several teams in playoff races were struggling. His club stumbled again heading into a weekend series at Kansas City.
Javier Vazquez (12-14) was ragged on three days' rest, and second baseman Alexi Ramirez let a grounder skip through his legs as the Yankees made it 7-1 in the fourth inning. Midway through the sixth, Ken Griffey Jr. and more than half of Chicago's starters had been pulled.
"I think we're missing something. I don't know what it is.
Hopefully, we can get it back," White Sox shortstop Orlando Cabrera said.
Guillen wants to rely on his best pitchers down the stretch, and Vazquez made his first outing on short rest since 2004 - he's 0-3 in such starts. The White Sox lost three of four in New York, and Guillen called the series "horrible."
The Yankees are almost sure to miss the postseason for the first time since starting their run in 1995. The feel is certainly different at Yankee Stadium - Derek Jeter went over to a group of White Sox during batting practice and wished them well, should they reach October.
With only three games left before their ballpark closes, the Yankees would like to avoid being eliminated at home. New York also pulled some of its starters early, including Alex Rodriguez and his newly dyed blond locks, and won for the fifth time in six games.
"It was an example of how we could've played all year," Mussina said.
Mussina (18-9) earned his 268th win, tying Hall of Famer Jim Palmer for 33rd on the career list. He gave up one run and five hits in six-plus innings, and still has a chance for his first career 20-win season with starts left at Toronto and Boston.
"The last ones are always the tough ones," he said.
Mussina waved his cap as he left the mound after Brian Anderson's leadoff double in the seventh. The crowd of 53,152 gave him a nice ovation.
"I won the last game I pitched at Yankee Stadium. It was worth tipping my hat," he said.
Abreu picked on a familiar victim, hitting an upper-deck shot to right and another long drive off Vazquez. Abreu has nine home runs in 71 at-bats against the White Sox righty - the Yankees star has more career homers and at-bats off Vazquez than any player in the majors.
"I feel very comfortable against him," Abreu said.
Abreu also had a two-run single on the first pitch from Horacio Ramirez and an RBI grounder. Paul Konerko hit a solo home run for the White Sox.
Notes: Abreu had his 13th career multihomer game and second this year. ... Yankees RHP Humberto Sanchez, from South Bronx High School, and C Francisco Cervelli made their major league debuts when they entered in the eighth. ... Yankees OF Johnny Damon missed the game. He was with his wife after she gave birth earlier in the day to daughter Danica. The name, Damon relayed through manager Joe Girardi, was not inspired by race driver Danica Patrick. ... Emilio "Millito" Navarro, the oldest living professional baseball player, threw out the ceremonial first pitch. Still spry a week before his 103rd birthday, he warmed up his arm, waved his hat and made a 30-foot toss on the fly to catcher Jorge Posada. Navarro played for New York's Cuban Stars of the Negro Leagues in 1928-29, but had never been to Yankee Stadium. Asked how the game had changed, his eyes widened and he mentioned the high salaries. "I made $25 a week," he said through a translator. ... Among Guillen's fondest memories of Yankee Stadium: "I got my only five-hit game here." He did it on July 9, 1987.
