The tournament's 12th seed eventually pulled off the 17-21, 21-14, 21-17 win in one hour and nine minutes against 20-year-old Sen.

After conceding the first game, the former world number one got off to an explosive start in the second with a flurry of smashes as he took full control of the rest of the tie.

In the other men's singles semi-final, unseeded Loh Kean Yew of Singapore upset third seed Anders Antonsen of Denmark in straight games 23-21, 21-14.

Loh, ranked 22^nd in the world, could become the first unseeded men's singles world champion since 2013 when China's Lin Dan returned after a year of relative inactivity to defend his 2012 world title.

The 24-year-old has already created history after becoming his country's first player to make it to the semi-final stage.

Loh has attracted a lot of attention at the tournament, mainly because of his 14-21, 21-9, 21-6 shock victory over world number one Viktor Axelsen of Denmark.

Victory in Huelva would cap off a fantastic year for Loh who won the Dutch Open in October and the Hylo Open in November before finishing as runner-up in the Indonesia Open.

A more established match-up is in store in the women's singles final as first seed Tai Tzu-ying of Chinese Taipei takes on Japan's second seed Akane Yamaguchi.

The Tokyo 2020 silver medallist Tai beat China's He Bingjiao 21-17, 13-21, 21-14 in a thrilling back-and-forth fixture.

Yamaguchi meanwhile triumphed 21-19, 21-19 in straight games against He's countrywoman Zhang Yiman to set up her 19^th meeting with Tai.

Tai, the world number one, has won 12 of their matches while Yamaguchi has claimed six.