CHICAGO -- Asked before his first game back in the Windy City as an opponent if there was a particularly special moment from his 16 years with the White Sox that stood out, Frank Thomas didn't bite.

"There's been a lot of special moments here," he said. "A lot of special moments."

A couple of hours later came three more, in rapid succession, and about an hour later came yet another. But the A's managed to blow the four-run lead Thomas played a huge hand in creating and fell, 5-4, in the opener of a three-game series at U.S. Cellular Field.

Pinch-hitter Rob Mackowiak tore into the first pitch he saw from A's closer Huston Street with two outs in the bottom of the eighth inning for a game-tying two-run homer, and Pablo Ozuna ended it with a two-out bunt single off lefty Ron Flores in the 10th.

"It's bittersweet," Thomas said of his night. "It's about winning, and we didn't get it done."

Thus, what should have been a triumphantly special night for Thomas, who hit two homers and a single in his first three at-bats, went wasted. So did Barry Zito's fifth consecutive strong start, as Oakland lost its third game in a row.

"It's a tough loss, it really is," Zito said. "We had the momentum going our way most of the night."

And most of that mo' was created by Thomas' moments.

No. 1: After Zito survived a rocky bottom of the first inning, a two-minute video tribute to the man South Siders nicknamed "Big Hurt" played on the massive screen looming over center field. Thomas, who was due up second in the top of the second, stayed in the A's dugout throughout, trying and failing to compose himself.

"It was touching to see the tribute," Thomas said. "It's hard to look at all that stuff."

Moment No. 2: After Eric Chavez grounded out, came a long and loud standing ovation as Thomas strode to the plate for his first at-bat. Before stepping into the batter's box, Thomas removed his helmet and waved it in every direction, soaking up the love.

"It was really nice," Zito said. "We know what a great guy Frank is, and it was nice to see the fans know it, too."

Moment No. 3: Once the cheering subsided, Thomas worked Sox starter Jon Garland into a 3-1 corner, got the fastball for which he was clearly looking and hammered it 402 feet into the left-field bleachers for the 456th home run of his career. Again the crowd came to its feet, applauding the familiar sight of Thomas rounding the bases.

"It was a great homecoming; I can't deny that," Thomas said. "I've been looking forward to coming back here just to show people I'm not dead."

An inning later, a mini-moment; he smoked a line drive into the left-field corner that would have been an easy double were it not for his still-tender right thigh muscle. He settled for a long single that pushed Mark Kotsay to third, from whence he scored on a single by Bobby Crosby, who had followed Thomas' homer in the second with one of his own.

"It should have been a double, but I tried to take off [around first base] and I felt the quad a little bit," Thomas said with a wince. "It was disappointing that I didn't get a double on that."

And if, in a game that by the third inning had featured a four-minute squirrel-in-the-outfield delay and the ejection of Chicago manager Ozzie Guillen, Thomas hadn't already established himself as the story of the night, Moment No. 4 seemed to cement that status.

With two out in the fifth inning, Thomas jumped all over an 0-1 fastball from Garland and drilled it deep to left again. Career homer No. 457, his ninth with the A's, gave Zito a 4-0 lead.

"I'm comfortable in this park," Thomas said. "I've probably had 3,000 at-bats in this park. I see the ball well here."

Said Guillen: "I think we forgot how to pitch to Frank. We have to find out the next couple of days how to pitch to him. ... There are a lot of ways to pitch to Frank, and we didn't pitch good to Frank today."

Fighting command problems throughout, Zito weaved his way through six innings, allowing a run on four hits and six walks before leaving with a pitch count of 112. Zito has a 0.80 ERA in five starts this month, but thanks to a lack of run support and bullpen failures, he's only 2-1 in that span.

Injuries to relievers Justin Duchscherer and Joe Kennedy, both on the disabled list, left the A's relying Monday on three pitchers who started the season at Triple-A.

"It's a lot to ask the bullpen to hold a good hitting team like this down [for three innings]," Zito said. "We've kind of had a turnstile, or revolving door down there. I have to find a way to give us more."

Kiko Calero worked a shutout seventh for the A's, but the tide shifted considerably in Chicago's favor thereafter. Thomas was greeted with a smattering of boos before striking out in the top of the eighth, and former A's outfielder Jermaine Dye drilled a solo homer off Steve Karsay to open the bottom half and make it 4-2.

Karsay was replaced with one out by Randy Keisler, who gave up a two-out double to Juan Uribe and was replaced by Street, who suffered his third blown save of the season when Mackowiak yanked his initial offering into the A's bullpen.

"First-pitch changeup, I definitely didn't think he'd hit a homer," Street said. "I was just trying to get ahead, 0-1. He was coming off the bench, and I figured he'd be sitting on a fastball the first pitch. Credit him for whacking it."

Street worked a perfect 10th inning, and Thomas' night took another unfortunate turn when the White Sox, after a double by Kotsay off closer Bobby Jenks, intentionally walked Chavez to get to Thomas. Kotsay took third on a passed ball and Chavez stole second before Thomas popped up in foul ground and Crosby struck out on three pitches to set the stage for the dramatic finish.

With runners at the corners and two out, Ozuna pushed a bunt to the right side of the mound that first baseman Nick Swisher scooped up before throwing wide to second baseman Marco Scutaro, who was covering first.

"We talked about the guy before the game, how to defense the bunt," said A's manager Ken Macha. "It wasn't a surprise. He put it in a perfect spot."

Swisher concurred, saying Ozuna likely would have beaten it out even if his throw had been accurate. He also expressed remorse about not being able to pull out a win on Thomas' big night, and even Ozuna seemed to feel for his former teammate -- to an extent.

"He played here his whole career and there were a lot of emotions," Ozuna said. "He did good in front of his fans, but No. 1 is that we won the game."