Juan Martin del Potro defeats John Isner to win Citi Open

Juan Martin del Potro has won the Citi Open with a 3-6 6-1 6-2 defeat of John Isner in the final in Washington DC.

The Wimbledon semi-finalist was slow out of the starting blocks, struggling to contend with the American's powerful serve in the first set.

Isner took the opener 3-6 but Del Potro found his stride in the second, breaking his opponent twice in the set to claim it 6-1 and storming through the first game of the decider.

The Argentine broke Isner at 4-2 and withstood three break points to serve out the match and wrap up the tournament.