Playing in full view of a out-of-town scoreboard teasing them with the results of the Red Sox-Rangers game in Arlington, the Yankees were unable to improve their lead in the American League East past 7 1/2 games, even after Boston's loss.
The Yankees watched their final lead evaporate in the fifth inning, as Franklin Gutierrez tied the game with a two-out RBI single to center and Jack Hannahan followed with a single to right. Chamberlain had earlier allowed a two-run double to Jose Lopez, allowing seven hits while walking three and striking out two.
"I'm continuing to throw strikes," Chamberlain said. "I'm not walking a ton of guys. I'm getting them swinging early in the count. When you go at them and attack them, they're aggressive. You've just got to continue to do it. I haven't been that bad."
Chamberlain came out of the All-Star respite on fire, talking about clearing his mind in a Nebraska backyard and translating results by limiting opponents to an 0.83 ERA in three victories after his return.
But his three starts since then have been rather ordinary -- in the 16 August innings that followed, Chamberlain has allowed 12 earned runs on 15 hits.
"He threw the ball great coming out of the break, and today he went right through the first two innings quickly," manager Joe Girardi said. "He left some sliders up today, which he doesn't do very often. I thought he had a good fastball and some trouble with his slider today."
Because of a staggered schedule to permit him extra rest as the Yankees advance down the stretch in view of October, Chamberlain is not expected to pitch for eight days, next starting on Aug. 25 against the Rangers at Yankee Stadium.
"I'll try to learn as much as I can, not being on the mound," Chamberlain said. "I've got great guys around me to help. I think that's the biggest thing, being able to better myself reading swings and reading guys' feet and how they approach the plate. That's the only thing I can do."
Derek Jeter drove home the game's first run and hit the history books with the same swing, connecting for an RBI double in the third inning off Seattle starter Doug Fister.
The hit was Jeter's 2,674th as a shortstop, surpassing Luis Aparicio for the most in Major League history. Jeter finished 3-for-4 in the loss and said that he was surprised to learn of the achievement.
"I don't ever sit around and look back on anything that we've done," Jeter said. "It's just more of what you can do to try and improve. That's what you try to do, year in and year out.
"I think being consistent is something that gets overlooked at times, but I think every player strives to be consistent. That's all you can do."
Nick Swisher belted a two-run homer to center off Fister in the fourth, his 20th of the season and 17th away from Yankee Stadium.
But that was all the Bombers would manage, as Fister completed seven innings in holding New York to eight hits while walking none and striking out four to log his first Major League win.
"He was mixing it up," Jeter said. "His fastball moves a lot, and he was mixing his offspeed pitches. He wasn't falling behind guys and he had good control. He pitched a good game against us."
"We couldn't really get anything going off of him," Johnny Damon said. "It's one of those unfortunate days. Stuff happens, but we're definitely not happy about it."
Reliever Alfredo Aceves struggled with his control in the seventh inning, hitting Josh Wilson in the back with the bases loaded to force in Ken Griffey Jr. with Seattle's fifth run.
Ichiro Suzuki greeted Chad Gaudin with a two-run single to right that broke the game open, and Kenji Johjima added on with a solo homer in the eighth inning as the Yankees lost for just the seventh time in 30 games.
"It's going to happen sometimes," Girardi said. "It hasn't happened to us in a long time, so it's unusual to see. But it happens."