Defending champions Zhang Jike and Li Xiaoxia from China will face a tough challenge at the upcoming World Table Tennis Championships which start in eastern China's Suzhou on Sunday.

Zhang, who won the men's singles title at the 2013 World Championships in Paris, was drawn into bottom half on Saturday alongside with the likes of world No. 2 Xu Xin from China, Japan's world No. 5 Jun Mizutani and Belarussian veteran Vladimir Samsonov.

"I think the draw is quite normal. If you want to reach the final at the Championships, you have to beat all you opponents on the road," said Zhang. "Of course I want to defend my title, but my opponents will pose real threats to me, so I will try my best in the tournament."

Chuang Chih-Yuan from Chinese Taipei and Zhang's teammate Fang Bo were also drawn into the bottom half.

World No. 1 Ma Long of China is clear favorite in top half to reach the men's final, and he hopes to have another blockbuster final against Zhang, his teammate and longtime rival.

"I never reach the final at the Championships, so I will take the tournament as a platform to showcase my skills and hopefully I can meet Zhang in the final," Ma said.

Ma, who is desperate to claim his first singles champion in table tennis worlds, will possibly clash with stars including his doubles partner Timo Boll of Germany, world No. 4 Fan Zhendong of China, world No. 6 Dimitril Ovtcharov of Germany in the top half actions.

Li Xiaoxia, women's singles defending champion from China, faces a tough bottom half with world No. 2 Liu Shiwen and world No. 6 Zhu Yuling from China.

Li, who is still suffering an injury, admitted that she is not in the best shape coming into the World Championships.

Li said: "I'm still recovering from my injury. For an athlete, health and body conditions are the most important thing. It's even so when you try to become the best player in China."

Li's teammate and world No. 1 Ding Ning has been drawn into top half alongside with world No. 4 Feng Tianwei of Singapore, world No. 5 Kasumi Ishikawa from Japan and world No. 7 and teammate Wu Yang.

Ding is looking for her second singles title after triumphing in 2011.

A total of 310 male and 238 female players from 100 federations will compete in Suzhou.