(Adds fifth set)
NEW YORK, Sept 10 (Reuters) - Olympic champion Andy Murray of Britain won the U.S. Open title in five sets, beating last year's winner Novak Djokovic of Serbia 7-6 7-5 2-6 3-6 6-2 on Monday.
Djokovic, frustrated by high winds on Saturday in his semi-final before the match was suspended until Sunday, struggled in Monday's wind and was broken in the first game after four unforced errors and double-faulted to lose serve in the fifth.
Murray also lost his first serve after three unforced errors but looked to be dealing better with the blustery gusts until Djokovic began finding the range and moved the Briton around the court for a service break that levelled the match 4-4.
As both players began adapting to conditions, the set featured some spectacular rallies and went to a tiebreaker. Murray dominated but squandered five set points before Djokovic sent a service return long to end it 12-10 in Murray's favour.
Both players registered 19 unforced errors in the pressure-packed, 87-minute opener played in difficult conditions.
Djokovic seemed to suffer a letdown after dropping the marathon tiebreaker and Murray pounced with breaks in the Serb's first two service games to charge into a 4-0 lead.
The 25-year-old Australian Open champion got one service break back in the fifth game when Murray ran off a string of unforced errors.
Olympic champion Murray was serving for the set at 5-3 but another three unforced errors helped Djokovic break him to bring the set back on serve at 5-4.
Murray, however, broke Djokovic in the 12th game, taking advantage of a missed overhand by the Serb to claim the set on a forehand that sailed long and put the Scotsman in position to claim his maiden grand slam crown.
After falling behind early in the first two sets, Djokovic grabbed the early initiative in the third.
He broke Murray's serve in the third game to lead 2-1 after the Scotsman double-faulted to give Djokovic two break points and he took the first with a return winner as the match clock ticked past three hours.
Murray had a couple of chances to break back but was unable to seize his opportunities and then fell behind 5-2 when he lost another service game as Djokovic pumped his fists and the crowd roared.
Djokovic served out the set, the quickest of the match so far, to keep the contest alive.
Revitalised after winning the third set as the wind started to die down a little, Djokovic made a flying start to the fourth when he broke Murray's serve in the opening game.
He set up the break with a cheeky drop shot then ripped a winner past Murray to lead 1-0 then held his own serve to consolidate his break as the Scotsman began to show signs of weariness.
Murray fended off a break point in his next service game as the floodlights were illuminated then missed a chance to break back as the next six games went with serve and the match clock ticked past four hours.
Djokovic sealed the set with another break, giving him the advantage of serving last in the fifth, when Murray dumped a backhand then another over the baseline.
The last time anyone came back from two sets down to win the U.S. Open final was in 1949 when Pancho Gonzales beat Ted Schroeder 16-18 2-6 6-1 6-2 6-4.
Murray, however, was intent on making his own history and broke the five-times grand slam winner in the first and third games to lead 3-0 and bring the Flushing Meadows crowd to their feet.
Djokovic once again showed his fight, breaking back in the next game and closing to 3-2, needing another break to bring the decider back on serve.
The 25-year-old Briton denied Djokovic by holding his serve at love to lead 4-2 before effectively ending the Serb's hopes by breaking his serve to lead 5-2.
The world number two received treatment for a groin strain during the change-over but Murray was not unsettled and ended the four hour, 54-minutes duel in the next game when Djokovic sent a forehand long.