This was meant to be the year when Roger Federer would equal, if not break, Pete Sampras's record of 14 grand slam titles.

Instead, it was a season in which Rafael Nadal finally spread his tentacles beyond Roland Garros. The Spaniard first grabbed Federer's Wimbledon crown, then snatched Olympic gold in Beijing.

Spain's Rafael Nadal and Roger Federer of Switzerland pose for a photo before the men's singles final match at the Wimbledon tennis tournament in London, capital of Britain, on July 6, 2008.

That failed to satisfy Nadal's hunger and he went on to end Federer's record 237-week reign as world number one just hours after the Olympic medal had been placed around his neck.

"Almost a perfect season, no?" quipped the 22-year-old Nadal, who took his grand slam tally to five.

While Nadal's rampaging run heralded a new era for the men, the women's game also underwent a changing of the guard -- albeit rather unexpectedly.

Justine Henin stunned the tennis world when she abruptly abdicated her position on top of the rankings by quitting the sport 11 days before she was expected to defend her French Open title in May.

"I have been driving my career based on an emotion but I didn't feel that emotion any more...it's the end of a wonderful adventure," the seven-times grand slam champion said.

The 25-year-old Belgian became the first woman to walk away from tennis while ranked number one and her absence sparked a mad scramble for the top spot.

In the last six months, the battle for supremacy became so intense that the top spot changed hands six times until Serbia's Jelena Jankovic won the final round of musical chairs to clinch the coveted year-end prize.

For much of the season though, prizes were in short supply for Federer. He had high hopes of erasing Sampras's name from the record books in 2008 as he started the year as the owner of 12 grand slam trophies and as the defending Australian Open, Wimbledon and US Open champion.

Dream died

That dream effectively died less than four weeks into the New Year when, suffering from a bout of glandular fever, the Swiss relinquished his Melbourne Park title with a semi-final defeat to eventual winner Novak Djokovic.

After failing to reach a slam final for the first time since the 2005 French Open, Federer acknowledged: "I've created a monster...it's not easy coming out every week trying to win."

Federer was vanquished in the Roland Garros and Wimbledon finals -- on both occasions by his personal bogeyman.

The irrepressible Nadal enhanced his reputation as arguably the greatest claycourt player when he swept aside Federer with embarrassing ease, dropping only four games, in the French Open final to lift his fourth successive title in Paris.