Later, Baghdatis’ legs locked up, and he dropped to the ground. But he got up and continued to play.

“I just wanted to fight,” said Baghdatis, who attributed his cramps to stress. “I wanted to stay on the court. I’ll do anything to win.”

Agassi had appeared to be in control after the first two sets since he had won all previous 58 matches at the Open with that size lead. And he was up 4-0 in the fourth set, before winners began to come more frequently from the racket of Baghdatis, who knew his role going in, saying: “Sure, I’m the bad guy for tonight.”

Agassi and Baghdatis share a sponsor and wore shirts with the same weblike design. The difference: Agassi’s was country club white, while Baghdatis’ was a neon orange. And the kid topped off his look with a hip headwrap, the sort of thing Agassi might have donned a decade or more ago.

The clock might as well have been turned back, though, the way Agassi smacked balls from inside the baseline, the thwack from his racket echoing off the court’s walls. He was having a great time, plain and simple, just like his wife, former star Steffi Graf, who was smiling and clapping in the stands. Agassi saluted the crowd when it did the wave in the third set. When Baghdatis sailed one lob long, ending a point, Agassi went ahead and hit the ball through his legs anyway, as if to say: “Hey, I’ve still got it.”

But Baghdatis, an up-and-coming star who reached the Australian Open final and Wimbledon semifinals this year, wouldn’t make it easy, even after he tumbled and hurt his left wrist in the first set. He was visited by a trainer, who gave him some pain pills, and Baghdatis’ two-fisted backhand gave him fits.

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Still, Baghdatis began yelling, pounding his chest, drawing some boos.

“That’s life,” he said. “It could be unfair, but so many things happen that are unfair in life. ... You can’t cry about it.”

An animated Baghdatis shook off a shanked overhead by laughing and crossing himself, and when Agassi eventually trailed, Graf covered her mouth, the picture of worry.

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Baghdatis finished with 86 unforced errors, 39 more than Agassi, an eight-time major champion and one of only five men with a career Grand Slam.

Because Agassi went only 8-7 this year before the Open, he’s unseeded, which is why he had to face someone ranked as highly as Baghdatis so early.

Not only did they put on quite a show, but Agassi also provided the day’s signature moment even before swatting a ball: After a morning practice session, he autographed a teen’s forehead with a marker, making sure the final “i” was dotted.