Justin Gimelstob was the top junior in American tennis in the early 1990s. He was the country's top collegian as a UCLA freshman. But life on the pro circuit has been a decade-long exercise in humility and, increasingly, pain.

In an effort to climb back into the top 100, Gimelstob (currently ranked 123rd) underwent his 13th cortisone injection last week in London -- an essential measure, he said, after a chronic back injury flared up and forced him to default in his final qualifying match for Wimbledon. Like previous injections, the shot worked. Better still, days later he earned a place in the 128-player Wimbledon draw, rewarded with a "lucky loser" spot after another player withdrew.

Gimelstob's fortunes surged again on Wednesday when he ousted Chile's Nicolas Massu, 6-3, 4-6, 7-6 (7-5), 7-6 (7-0), to advance to Wimbledon's third round -- a feat he hadn't pulled off since 2003. It might be enough, he said in his post-match interview, to nudge him into the top 100, where he hasn't been since 2000.

Post-match interviews are highly structured here, with tournament officials escorting each player into an auditorium at an appointed time, then cutting off reporters' questions after 10 or 20 minutes, depending on the player's stature, so that the next interview can begin. For most players, the official warning -- "One last question, please" -- is greeted with relief, a signal that the unpleasant probing into their psyche and strategy is about to end.

But Gimelstob -- out of the spotlight for so long after being relegated to second- and third-tier events in remote corners of the world -- had no interest in cutting things short.

"This is my moment!" Gimelstob blurted out, turning to the official minding the interview clock. "You don't understand where I've been. Let them learn! Let me get my opinions across!"

What followed was some rare insight into what life as a professional tennis player is like, at least for the hundreds of contenders without automatic berths, lucrative sponsorships or a team of agents, trainers, masseuses and managers in tow.

Gimelstob acknowledged that taking so many cortisone shots was dangerous, explaining that most doctors advise taking no more than three in one year, for no more than three years. "I'm well past that," he said. "We're kind of going in uncharted territory."

But, he added: "I've invested a lot in this. Everyone has -- my family, my friends, my coaches. I feel this desire and this need to eke out every ounce of talent that I can drag out of my body and my tennis because, you know, there's obviously going to be a time when I can't do that. I just want to make sure that I got everything out of it that I could."