Wawrinka sets up Nishikori clash in US Open semis

Two-time Grand Slam champion Stan Wawrinka battled past a tiring Juan Martin del Potro of Argentina in four sets to advance to the semi-finals of the US Open at Flushing Meadows in New York on Thursday.

The Swiss third seed, who went down in the second set, posted a 7-6(5), 4-6, 6-3, 6-2 win over 2009 champion del Porto in a thrilling last eight contest of the men's singles event that lasted three hours and 12 minutes.

Describing del Porto as an 'incredible player', Wawrinka admitted that it was one of the toughest matches of his career both mentally as well as physically, Sport24 reported.

Wawrinka, who will be playing his third US Open semi-final in four years, has now set up a clash against Japan's Kei Nishikori, who made it into the last four after stunning second-seed Andy Murray

1-6, 6-4, 4-6, 6-1, 7-5.

Meanwhile, the other semi-final clash will see defending champion and world number one Novak Djokovic take on 10th seeded Frenchman Gael Monfils for a place in finals.