Two-time champion Rafael Nadal has been knocked out of Wimbledon by Belgium's Steve Darcis in one of the biggest shocks of recent years.Darcis, ranked 135 in the world, beat the Spaniard 7-6 7-6 6-4 in their first round match on Court One.Nadal, who won the French Open earlier this month, also suffered a shock early elimination at Wimbledon last year when he lost to Lukas Rosol.The 12-time Grand Slam winner, who was seeded fifth for this year's tournament, could have faced Roger Federer in the quarter-finals and Andy Murray in the last four.