New York: Sixth-seeded Briton Andy Murray reached his first Grand Slam final in commanding style by upsetting world number one Rafael Nadal 6-2 7-6 4-6 6-4 at the US Open on Sunday.

The shrewd Scot outplayed the Spanish left-hander in a semi-final contest that began on Saturday on the Louis Armstrong court and ended more than 24 hours later in the showpiece Arthur Ashe Stadium after being interrupted by the remnants of Tropical Storm Hanna.

Leading by two sets but trailing 2-3 in the third overnight, Murray lost the third set before breaking the Spaniard in the 10th game of the fourth, wrapping up the biggest victory of his career with a backhand winner.

The 21-year-old Briton will play four-times defending champion Roger Federer in Monday's final, the Swiss maestro having beaten Serb Novak Djokovic on Saturday.

“Very relieved,'' an emotional Murray said in a courtside interview on a sun-splashed, blustery afternoon after ripping 65 winners past Nadal, including 21 aces.

Murray, who will attempt to become the first British man to win a Grand Slam title since Fred Perry at the 1936 US Open, has a 2-1 winning record against world number two Federer.