Kei Nishikori secured Japan's first Olympic medal in tennis since 1920 - a bronze in men's singles - at the Rio Olympics by defeating Rafael Nadal 6-2, 6-7 (1) and 6-3, although the Spaniard fought back from a 2-5 disadvantage in the second set to a tiebreak to send the match into a third set.Nadal, who won the gold in the singles competition in Beijing in 2008, was tired -- playing in his 11th match at this year's Games -- with his bitter three-set loss to Argentina's Juan Martin del Potro in the semi-final leaving him exhausted, reports Efe.Nishikori delivered three aces in the first set and scored a phenomenal 73 percent on his second serves, breaking Nadal twice, although he failed to break the Spaniard six other times on Sunday. Nevertheless, Nadal committed eight unforced errors and Nishikori was able to handily take the set.The second set ended in Nadal's column after the tiebreak, but Nishikori dominated the third set from the outset, although Nadal was able to hold his serve and fought hard even though defeat came ever closer and he ultimately went down 6-3.Nishikori, ranked No. 7 in the world, is a real warrior on the court who places very good shots, but he had been unable to best second seed Andy Murray in the semi-finals, where he lost in straight sets, allowing the 29-year-old Scotsman to advance to the final.