Time may be relentless in tennis, ending careers earlier than in many other sports.  But a trio of ATP veterans have defied time and the injuries associated with it to extract drain drop of success from their careers.

After defeating Juan Martin Del Potro in the second round of this year’s US Open, the 32-year-old Lleyton Hewitt described what an emotional win it was for him.

“It's an amazing feeling,” said Hewitt. “For me, just going back in the locker room afterwards I sort of had to pinch myself.  A year and a half ago, I got told I would probably wouldn't play again with the surgery I had. For me, I love being out in that atmosphere, sucking up every second of it.”

For players like Lleyton Hewitt, Tommy Haas and Tommy Robredo, age and health seem to be constantly fighting and working to break down their resilience and desire to continue to play the game they love. But what ultimately keeps them hungry and from hanging up their rackets is the recognition that there is still more glory out there for them, more moments to cherish in the future.

Hewitt, for example, is a two-time major champion and a former world No. 1. Despite the fact that his days of dominance lie well behind him, he plays each day knowing that there are still some magnificent moments to be had out on the tennis court.

 “Even when I was No.1 in the world I was taking it one match at a time.  I never was a player to look too far ahead, the way draws can pan out and stuff,” Hewitt said when asked about his mentality going into majors.

Watching one of the veteran Aussie’s matches, it is crystal clear that he has not skipped a beat. He scraps and claws for each point from start to finish, whether it be the first round of qualifying or the final. He wants to win so badly because he knows what he can extract from his on-court success is far greater than what can be taken away from him during his periods of inferior play or injury.

After stunning Novak Djokovic in the fourth round of Miami this year, the 35-year-old Tommy Haas echoed Hewitt’s sentiments.

“Like he just said, this is what you play for, or I play for,” affirmed Haas. These are the moments I appreciate the most, going on those big stadiums, big stages, playing against the best people in the world.”

When considering Haas’ situation, one should recall exactly what the German has gone through just to be able to step foot on a tennis court again.  Between January 1996 and March 2010, Haas had right ankle surgery, left ankle surgery, right shoulder rotator cuff surgery, arthoscopic surgery on his right shoulder, right hip surgery, and right elbow surgery. In addition, his parents were involved in a motorcycle accident in 2002, causing him to take a significant amount of time away from the game to care for his parents. Haas also had the serious misfortune of spraining his ankle during the warm-up of a 2005 Wimbledon first-round match against Janko Tipsarevic.

Notwithstanding that extraordinary catalogue of injury and misfortune, the German stayed committed to seizing many memorable moments of glory.  Before his eye-catching upset of Djokovic this spring, those included his victory over world No. 1 Andre Agassi in 1999 and his win over Roger Federer in the final of Halle in 2012.

After defeating Federer in the fourth round of the US Open, the 31-year-old Tommy Robredo was asked by reporters whether he had a feeling coming into the match that he would overcome his 0-10 record against the Swiss. His response sums up the feelings of these hard-working veterans who still see much to gain from their careers.

“You never know what is going to happen, no?” Robredo asserted. And he is right. These guys continue to put their best foot forward against the world’s best because they know that a window of opportunity remains for them to grasp the spotlight and shake up the status quo.

Highlighted by quarterfinals at both Roland Garros and the US Open, Robredo’s season has marked an impressive comeback for someone who was unsure that he could recover from his leg injury and gain the necessary confidence to be successful on tour.

“One year ago I was 100 something, trying to come back,” said Robredo.  I wasn't sure if my leg will be perfect or not.  You have the doubts, no, that if your body's going to respond, and your tennis, if you're going to get the confidence back.”

Tennis has some unfortunate realities. One of these is that injuries do happen and can redirect a player’s career in an unexpected and unwanted direction. A second reality is that age will eventually catch up to all of us.

But what must also be said is that age and injuries are can be fought to the finish, just like a talented opponent. And if a player has the appetite for that fight, as Hewitt, Haas, and Robredo have proven, far greater rewards often reward them for their persistence.