Fourth ranked Chen Long of China was beaten in round one of the BWF Thailand Open ©Getty Images

The withdrawal of many top seeds in the Badminton World Federation (BWF) Thailand Open has left the field wide open in both the men's and women's events.

The top two ranked players in the men's competition – number one seed Kento Momota of Japan yesterday due to a thigh strain and China's second ranked Shi Yuqi – both pulled out ahead of the tournament at Huamark Indoor Stadium in Bangkok.

In the women's contest, Japanese duo Nozomi Okuhara and Akane Yamaguchi, along with P.V. Sindu, ranked second, third and fourth respectively, all withdrew before the draw was made for this BWF Super 500 event. 

Today saw the first round matches take place in Bangkok, and another singles seed has fallen: fourth ranked Chen Long of China was beaten by Taiwan's Wang Tzu-wei in straight sets, 21-13, 21-18.

That leaves number three seed, Chou Tien-chen of Taiwan, as the highest ranked men's player remaining.

Chou progressed to round two with minimal fuss, beating South Korea's Lee Dong-keun 21-13, 21-13.

Seventh seed Kanta Tsuneyama of Japan - for who the path to the semi-finals has opened up after Momota's withdrawal - battled his way into round two after a 66-minute victory over Sourabh Verma of India, 23-21, 19-21, 21-5.

In the women's singles, top seed Chen Yufei of China won in straight sets ©Getty Images
In the women's singles, top seed Chen Yufei of China won in straight sets ©Getty Images

There are no seeds left in the bottom quarter of the draw however, following's Shi's withdrawal and the 21-23, 21-11, 21-5 defeat of eighth seed Sameer Verma of India Malaysia's Lee Zii Jia.

In the women's singles, top seed Chen Yufei of China beat South Korean 17-year-old An Se Young 21-12, 21-17.

"No matter who I have to play against, I just convince myself that each match is a learning experience because I am still so young," said An after her defeat.

The other four remaining women's seeds are also into round two, including Thailand's number six ranked Ratchanok Intanon, who delighted the home crowd by beating Yvonne Li of Germany 21-13, 21-8.

"My opponent was well prepared and I made some early mistakes but then I relaxed and decided to play my usual game so that I will be comfortable," Intanon said. 

"This tournament will be just as tough as any other no matter who is competing and I intend to get the best results possible to get points to qualify for the Tokyo 2020 Olympics."

Competition is due to continue tomorrow with round two of the men's and women's singles.