Stunning, unexpected losses by teams or individuals are not an insignificant component to professional sports. They are, in fact, integral to the health of sports, as upsets sustain interest and provide at least temporary relief when monotony appears to be running roughshod over drama.

Tennis is no exception. The upset is a near constant in Grand Slam events as most recently illustrated at the French Open when Rafael Nadal, thought to be impenetrable on the red clay, fell to Robin Soderling in the fourth round. It was undeniably one of the great upsets in the history of tennis, or any sport for that matter.

Alas, there will be no chance of defending Wimbledon champion Nadal being upset at this year's tourney, with the world number one's knees having relegated the Spaniard to the sidelines. But is there a chance that Roger Federer - who is vying for his sixth Wimbledon championship, and with it surpassing Pete Sampras' record of 14 Grand Slam titles - could lose to some previously unheralded player? Highly unlikely, but the slim possibility is always present. After all, the chance for an upset is one reason to watch the early rounds of a Grand Slam event.

And Wimbledon has been the site for many shocking and unthinkable defeats of the top seeds at the hands of players who were thought to be incapable of pulling off such feats. While upsets on the magnitude of the aforementioned Nadal loss last month are indeed once-in-a-generation occurrences, there are nonetheless many major surprises that have turned the tournament on its head and can forever alter the destiny and legacy of players.

Pete Sampras becoming just the latest casualty on a wild Wednesday in 2002, on the "Graveyard of Champions," no less. Maria Sharapova announcing her arrival with a dismantling of number-one seed Serena Williams in the 2004 Finals. Kevin Curren, an eight-seed, handing John McEnroe what was, at that time, his worst defeat as the world's number-one player in the 1985 quarterfinals.

It'd be folly to predict an upset during this year's Wimbledon fortnight, as upsets - hence their name - always appear to come from the least likely of sources. For proof, look no further then the Ten Greatest Upsets at Wimbledon from years past, the most important and storied of all tournaments.