Akane Yamaguchi has justified her top seeding ©Getty Images

Top seed Akane Yamaguchi has won a thrilling semi-final in the women's singles of the Badminton World Federation (BWF) Thailand Masters in Bangkok.

The Japanese star was pushed all the way by fourth seed Carolina Marín in the World Tour Super 300 event at Indoor Stadium Huamark.

The Spaniard won the first game 21-14 and a surprise looked on the cards.

However, Yamaguchi dug very deep to take the second game 23-21, before eventually sealing the win, 21-18, in the third.

In the final she will face South Korean third seed An Se-young.

An brought an end to the incredible run of unseeded Japanese player Aya Ohori, who defeated second seed Ratchanok Intanon of Thailand in the quarter-finals.

However, she couldn't repeat that performance, bravely losing 21-17, 21-14. 

In the men's singles semi-finals, Kenta Nishimoto brought an end to the run of unseeded home favourite Kunlavut Vitidsarn.

The Japanese player was always in control, winning in straight games 21-18, 21-13.

The other semi-final was more competitive, with third seed Ng Ka Long Angus of Hong Kong just too strong for second seed Shi Yuqi of China, coming through 21-18, 21-19.

Both finals take place tomorrow.