Despite their impressive resumes, Roger Federer and Serena Williams had to bounce back from rough times in the sport of tennis.

The 2008 U.S. Open was capped off by Federer and Williams winning their 13th and ninth Grand Slam titles, respectively.

Federer, despite winning 11 Grand Slams from 2004-2007, came into the U.S. Open “slamless” in 2008. A bout of mononucleosis weakened him in the year’s first half. He lost his No. 1 world ranking on Aug. 18 for the first time since 2004. He lost in the Wimbledon final to Rafael Nadal (the new No. 1) despite being the five-time defending champion, and was bludgeoned by Nadal in the French Open final 6-1, 6-3, 6-0.

Coming into the U.S. Open, Federer was not seeded first in a Grand Slam for the first time since 2004. All the talk was about Nadal’s new preeminence in men’s tennis and the idea that Federer had nothing left at age 27.

However, he silenced his doubters when he defeated Andy Murray 6-2, 7-5, 6-2 in Monday’s final. Federer became the first man of the Open era to win five straight Grand Slams at two separate events (the U.S. Open and Wimbledon). Afterward, he spoke of how much the match meant to him.

“It’s a different type of flavor, this one, no doubt. It means so much to me,” Federer had said, according to an interview conducted by the U.S. Open, of his 13th Grand Slam title, which puts him one behind Pete Sampras’ record.

Roger Federer, in his post-match comments, declared that he intends to stay at the top of the game for years to come, and is not done winning Grand Slams.

“I couldn’t stop at 13 [Grand Slams]. That would be terrible,” said Federer according to The Associated Press.

Serena Williams, 26, also came into the U.S. Open slamless in 2008. She had not been the world’s No. 1 since July 2003, and also tried to resurrect her career with a victory. In the eyes of commentators, women’s tennis was now all about Maria Sharapova, Ana Ivanovic, Jelena Jankovic and even Serena’s sister, Venus. Serena, however, was determined to fight the odds.

In 2006, Serena was ranked 95th in the world, and was seemingly an afterthought in women’s tennis. However, she never gave up on her career. The American tennis player began a steady climb up the rankings in 2007 and 2008, with the No. 1 ranking on her mind. She went on to win the U.S. Open, her ninth major, without dropping a set along the way. In doing so, she became the world’s top-ranked tennis player once again.

“It’s so special because I’ve been working so hard,” Serena told ESPN. “I feel like I have a new career.”

Federer and Serena are the two greatest champions of their generation. Federer is one Grand Slam away from tying the record for majors won. Serena revolutionized the sport with her incredible power, and transformed women’s tennis from a game of finesse and delicate ladies into a sport of built, muscular and superior athletes. When Federer lost his perch at the top of men’s tennis, most observers presumed he was done winning major titles. When Serena dropped out of the world’s top 50, those same observers wrote off her career entirely. However, they both beat the odds and are back at the top of tennis where they belong.