Andy and Jamie Murray have suffered a first-round exit at the hands of Austrian duo Jurgen Melzer and Alexander Peya in the men's Olympic doubles.
The British duo broke twice in the opening set to take it 7-5 but came unstuck 8-6 in a tie-break in the second.
With the brothers 4-3 up in the third, Melzer and Peya came back to win 7-5 and claim the surprise victory.
The Austrians will now take on the Spanish pairing of David Ferrer and Feliciano Lopez in the second round.
