The world tennis number one Novak Djokovic has worn down eighth seed Andy Murray in a gruelling quarter-final match at the US Tennis Open in New York.
In a repeat of the 2012 final, which Murray won, the pair combined for some stunning long rallies before Djokovic finally won in four sets - the first two of which went to tie break.
Djokovic the Wimbledon champion won the first set 7-6 and led 3-1 in the second only for Murray to mount a comeback and take the second 7-6.
But Djokovic always looked fresher and raced through the third set 6-2 and then took the fourth 6-4 with Murray struggling with back problems in the final set.
Djokovic will play Kei Nishikori in the semi finals with Nishikori becoming the first Japanese man for almost a century to reach the US Open semis after a five set win over the Australian Open champion Stan Wawrinka
Nishikori, the 24-year-old 10th seed, triumphed in four hours 15 minutes, his second marathon clash after needing four hours 19 minutes to get past Milos Raonic in the previous round.
Wawrinka was the third seed.
Russia's Ekaterina Makarova has reached the first Grand Slam semi-final of her career, downing former tennis world number one Victoria Azarenka 6-4 6-2 in the fourth round at the US Open.
Makarova, ranked 18th in the world, had fallen in four prior major quarter-finals.
But she out-played two-time Australian Open champion Azarenka, who was runner-up to Serena Williams at Flushing Meadows each of the past two years, but has hampered by injury in 2014.
The 17th-seeded Russian was steadier and more explosive with her big groundstrokes in dismissing the 16th seed from Belarus.
Makarova, who has advanced without the loss of a set, will meet either two-time defending champion and top seed Serena Williams or 11th seed Flavia Pennetta of Italy.