Argentina's Juan Martin del Potro has progressed to the last four of the men's singles of London 2012 by ousting Kei Nishikori of Japan in straight sets.
Del Potro broke at the first time of asking in the second game of the match but relinquished this advantage in the next.
As the first set neared the crucial stages, Del Potro broke again before giving away his serve again in the next.
However, the eighth seed broke the Japanese serve once more to take the set 6-4 in 48 minutes.
It was again Del Potro who broke early in the second but Nishikori managed to get back on level terms as the Argentine served for the match at 5-4.
Soon the pair were in a tie-break and it was Del Potro who managed to hold firm, winning the breaker 7-4 to seal his place in the semi-finals.
Del Potro, 23, will face either world number one Roger Federer or John Isner of the United States for a place in the gold-medal final at the All England Club.
