Suzhou (China), May 1 (IANS): Former World Youth Table Tennis Champion Fang Bo stunned World No.2 Xu Xin in an all-Chinese match to reach the men's singles quarterfinals at the World Championships here on Friday.

Fang, who jumped to fame in 2009 when he swept four titles at the youth worlds, nailed a 10-12, 7-11, 11-8, 11-2, 8-11, 11-9, 13-11 victory over left-handed Xu, who has been troubled with a muscle strain in the left shoulder, reports Xinhua.

Xu picked up the injury on Thursday night as he paired with South Korean Yang Hae-un to reach the mixed doubles final. Xu asked for an injury break while trailing 1-4 in the deciding set and returned to tie 10-10, 11-11 before his 23-year-old teammate took the game.

Earlier, top-ranked Ma Long played an aggressive top-spin game to beat the best defensive player in the world. The 26-year-old Chinese beat 17th-ranked South Korean Joo Sae-hyuk, 11-4, 11-3, 11-9, 10-12, 11-6.

Ma, 2012 World Cup winner, has been notoriously under-achieving in Olympics and World Championships, overshadowed by teammate Zhang Jike, who has completed a Grand Slam of Olympics, World Championships and World Cup singles titles.

Zhang, aiming for his third straight world singles crown, takes on Belarus veteran Vladimir Samosonov for a quarterfinal berth.

Joo, who plays a chop-and-attack game, had trouble in responding to firepower from Ma and lost the first two sets easily. As he put more spin to his chops and distracted his rival with counter-attacks, Joo narrowly lost the third set but won the fourth.

Using powerful forehand attacks coupled with placement shots, Ma didn't give a chance to an already jaded Joo, wrapping up in five sets. Ma will vie for a semifinal spot against the winner of Hong Kong's Tang Peng and South Korea's Lee Sang-su match.