World top-ranked Chinese Zhang Yining completed a "grand slam" of Olympic, world championship andWorld Cup singles titles by winning the singles final against Guo Yan here on Thursday.

As a dual Olympic champion Zhang hadn't faced much difficulty until she met club and national teammate Guo Yan. Experience counted as Zhang won 4-2 (5-11, 11-7, 11-4, 4-11, 11-8, 13-11).

Guo, world No. 8, had a high-flying start by taking the first set 11-4, which was the second set-loss for Zhang at the world championships.

Zhang snatched the next two sets before Guo dominated the fourth.

The determined Guo fought strongly as she saved three match points, rallying to 10-all from 7-10 down and then led 11-10 in the sixth set.

However, Zhang, who keeps a dominant 7-2 record over Guo since 2001, surged ahead again to 12-11 and forced Guo to return to the net for 13-11.

"I'm very happy that I won my first world singles title and realized my grand slam drema," Zhang said. "But at the same time I'm not happy with my performance as I didn't show my best form and technical advantages.

"My fighting spirit and the spectators helped me go through thedifficulties."

Zhang has been suffering a shoulder injury and stopped trainingfor a few days before the worlds.

"I was under great pressure. Fortunately I overcame my injury and burden, " she added.

While asked to compare herself with 2000 Olympic dual champion,also a grand slam winner, Zhang said: "From now on, all the glory has become the past. I am not a successor to Wang, but a teammate and good friend of her. She is still an outstanding player in the world."

Zhang and Wang, defending champions in the women's doubles, will play their semifinal against Tie Yana/Zhang Rui of Hong Kong,China, Friday morning.