NEW YORK -- For the aging Baby Boomer, retirement is a delicate balance of time and money. The lucky ones are able to dictate their terms.
For athletes, free will is rarely a factor. When the body quits on them, there is no choice. Not surprisingly, the celebrated competitors tend to linger as long as their limbs will let them.
Because we are fans, and emotionally involved, we feel their pain acutely when they perform below the scintillating standard they have set. It can be difficult to watch them play as parodies of themselves and, later, we hold it against them. Few -- you can count them on one hand by sport -- have the strength, desire and discipline to leave at the ultimate height of their game.
Pete Sampras won the U.S. Open four years ago and never seriously raised a racket again. Jerome Bettis walked away after the Pittsburgh Steelers won Super Bowl XL. John Elway won two Super Bowls with the Denver Broncos. Michael Jordan won three NBA titles and retired -- twice. Ray Bourque finally got his Stanley Cup with the Colorado Avalanche and skated off into the Canadian mist.
More often, it ends badly:
Willie Mays, Joe Namath, Muhammad Ali and Jordan (the third time, with the Wizards). Most recently, Zinedine Zidane ended his soccer career in disgrace with a disqualifying head butt. And, not soon enough, Brett Favre.
Which brings us to Andre Agassi.
Last year, in his 20th U.S. Open and at the age of 35, Agassi put together a breathtaking run that evoked memories of 39-year-old Jimmy Connors' improbable journey to the semifinals in 1991. Agassi beat James Blake in a ludicrous quarterfinal match that ended in a fifth-set tiebreaker, becoming the oldest Grand Slam finalist in more than three decades. That he lost to Roger Federer seemed somehow appropriate in a once-and-future king sort of way.
It was the perfect platform for departure into the dual world of parenting and philanthropy. His eight Grand Slam singles titles, including at least one of each major, place him in rare company that includes Sampras, Borg, Laver, Connors, Tilden and Lendl.
But Agassi did not take the easy out.
Almost everyone outside his immediate circle of friends -- me included -- thought it was a bad idea. He could only embarrass himself by continuing. What, exactly, was the upside?
When Agassi scuffled through the 2006 season, he confirmed all those predictions of doom. His back was in such bad shape that he passed on the Australian Open and French Open and played only four tournaments, losing to Bjorn Phau and Guillermo Garcia-Lopez, among others, before Wimbledon.
Back at the All England Club, one of his favorite places on earth, Agassi rallied briefly to win two matches before falling to Rafael Nadal in straight sets. He made halfhearted attempts at tournaments in Los Angeles and Washington and arrived at the Billie Jean King National Tennis Center with a record (8-7) more suited to, well, Guillermo Garcia-Lopez.
"Hindsight is 20/20," Agassi said after his difficult first-round victory over Andrei Pavel. "When you look at a year like I've had, it's easy to wish you didn't have to go through it. I needed to because for me I wanted to make sure I give everything I can and do this as long and hard as possible.
"To not compete this year, not to try to get myself through it, I would feel like I was quitting more than retiring. As much pain as it's been, it's been worth it for me to just put myself in a position where I can have clarity in my own peace of heart, peace of mind in the decision I'm making because I believe it affects more than just me."
This is the transcendent beauty of Andre Agassi. His motivation, he has said repeatedly, was to give the fans a few more memories. The cynical reporter imagined this was just a cover story from an athlete who was looking for a few more moments on the grand stage even if they amounted to table scraps.
The cynical reporter was wrong. So horribly wrong.
I didn't cry when they buried my father -- I wouldn't let myself. I didn't cry when they buried my sister. On Thursday night, with my family asleep upstairs, my eyes filled as Agassi and Marcos Baghdatis played out the fifth set of their moving second-round match.
Heading in, few gave Agassi a chance to win. Up two sets and 4-love in the third, Agassi couldn't lose. When the fiery Cypriot, playing with a sprained wrist, started to let his emotions leak into the match in the fourth set, he seemed destined to win. Then convulsive cramps sent him sprawling to the court and it looked like a mercy killing for Agassi. Then he (understandably) tightened in the moment, and Baghdatis found himself on the brink. Again.
After 3 hours and 48 minutes, Agassi won when Baghdatis' final backhand soared long. It was 12:38 Friday morning, and there were still at least 20,000 delirious patrons clapping and yelling. It was, according to some seasoned observers, the loudest sustained U.S. Open crowd in their memory, which is to say any match, ever. Joe Lynch, a former ATP communications specialist and working this week for the USTA, said it was the best tennis match he had seen in 15 years.
It didn't meet the scintillating standards of the Sampras-Agassi 2001 quarterfinal match that required four tiebreakers -- Baghdatis issued 86 unforced errors -- but in terms of pure drama and emotion, it might have been unparalleled.
This, of course, was the dizzying upside of non-retirement Agassi alone understood. We live vicariously through him, and fortified by a dozen standing ovations, he through us.
"It just seems like it's getting better and better -- just keeps getting topped," Agassi said. "I'm going to go out there and work hard and certainly try, but you're not guaranteed these moments, or that moment.
"To feel it out there was something I can keep with me forever."
As can we.
Nick Bollettieri, in the cauldron of his academy in steamy Bradenton, Fla., formed the player Agassi became. The coach was in the friends and family luxury box Thursday night watching his most charismatic pupil perform one more time. Earlier this year, they discussed Agassi's decision.
"He told me, 'Nick, if I can physically get out there and play, I'm going to give them one more year,'" Bollettieri said Friday, standing just outside Arthur Ashe Stadium. "The last two matches at the U.S. Open have proved beyond a shadow of a doubt that if you want to compete and have that kind of passion and attitude -- and a will to fight -- it can happen."
Steffi Graf, Agassi's better half, missed her moment. After winning six of eight Grand Slam singles titles in 1995-96, she lost her way for two years. Then, in 1999, she won the French Open, the last of her 22 major championships, and reached the final at Wimbledon, where she lost to Lindsay Davenport.
But the last match of Graf's marvelous career came later that same year in San Diego. She limped off the court, retiring from a second-round match against Amy Frazier with a left hamstring injury. The anguish that played across Graf's face during the Agassi-Baghdatis match left you wondering whether she was replaying that image in her mind.
"I've never seen Steffi so emotional," Bollettieri said. "I went to the bathroom four times during the fifth set."
Agassi fully understands that his chances of winning the tournament are very nearly zero. Thursday night's revelation? It doesn't matter.
"It's difficult now for so many reasons," Agassi said. "It's also inspiring now for many reasons. I mean, I haven't felt this. My whole career I've been striving to achieve things that I never believed I could do. I'm here now just taking it all in. That feels really special to me and really worth it.
"I've lived a dream for 21 years," Agassi said. "It's going to be impossible for me to be disappointed with a result when you have the support and feeling out there. This is why I chose here."
Greg Garber is a senior writer for ESPN.com.