It’s being called the biggest upset in the history of Wimbledon. Defending champion and current World No. 1 Novak Djokovic, was beaten by American Sam Querrey 7-6, 6-1, 3-6, 7-6 in the third round of the year’s most awaited tennis championship.

Querrey, seeded 28th in the tournament, and ranked 41 in the ATP rankings, started well leading by two sets when rain suspended play. When the match resumed on Saturday, Djokovic was determined to regain lost ground. He came back fighting to win the third set, but Querrey wasn’t about to let go of a chance to make history. Displaying ‘incredible calm’, he held his nerve and won the fourth set on a tiebreak, leaving spectators and Djokovic in a state of shock.

Last month, when he won the French Open, Novak Djokovic became the first player since 1969 to win four consecutive Grand Slams. He was looking forward to his third consecutive win at Wimbledon this year, having beaten Roger Federer in the finals for two years running — but Sam Querrey paid put to that hope.