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Video - Perez wins Mexico's first gold
Guillermo Perez won Mexico's first gold medal of the Beijing Olympics with victory in the men's -58kg taekwondo.
Perez defeated Yulis Gabriel Mercedes of the Dominican Republic in a decision after the bout ended 1-1.
Wu Jingyu won China's first taekwondo gold of the Games in the women's -49kg, beating Thailand's Buttree Puedpong.
Wu scored with a side-kick in the opening round and comfortably protected her lead as her 17-year-old opponent was deducted a single point.
The 21-year-old delighted the home crowd as she took the contest to the surprise Thai finalist, who never looked like upsetting the odds.
Wu's narrow one-point lead was never in danger and victory was secured when Puedpong was deducted a penalty point after being cautioned twice for passivity.
Men's champion Perez, who defeated Great Britain's Michael Harvey to reach the quarter-finals, scored early against Mercedes who left it late to respond, scoring seconds before the bell as he connected with a back kick.
Neither could add any final score in overtime and the judges declared Perez as the winner.
Rohullah Nikpai won Afghanistan's first Olympic medal as he claimed bronze, defeating world champion Juan Antonio Ramos, while the other bronze went to the defending champion Chu Mu-yen of Taiwan.
Chu's hopes of a historic defence of his title in Beijing were ended by Mercedes who won their quarter-final clash 3-2.
Taiwan is seen as a renegade province by China, which considers the island to be a part of its own country, but they can compete under the compromise name Chinese Taipei and Chu had been warmly received by the home crowd.
Relations between China and Taiwan have thawed in recent months and the prospect of Chinese Taipei's neutral white flag being hoisted in the event of a Chu victory would have been politically significant.
Chu, known as the 'War Lord of Taiwan', was seen as his island's best medal hope at this year's Olympics and he was cheered on by fans waving Chinese Taipei flags as he won his opening bout.
The crowd chanted "China" as he easily outclassed his Kenyan opponent Dickson Wamwiri, while one or two chants of "Taiwan" could also be heard.