Continuing her sizzling form, Indian badminton star P V Sindhu progressed to the summit clash of the World Tour Finals for the second successive time but it was curtains for debutant Sameer Verma in men's singles here on Saturday.

The 23-year-old Indian, who finished runner-up at the last edition, staved off a strong challenge from the fighting Ratchanok Intanon of Thailand, a 2013 world champion, to emerge a 21-16, 25-23 winner in a tense semifinal that clocked 54 minutes.

Sameer, however, had to swallow a bitter pill after squandering a match point advantage in the second game to go down 21-12, 20-22, 17-21 to All England Champion and World Championship silver medallist Shi Yuqi of China in the men's singles semifinals.

Sindhu came into the match with a 3-4 record against the Thai player but she was buoyed by her recent results as she has not lost to Intanon in the last two years.

The Olympic silver medallist will now fight for the title with Japan's Nozomi Okuhara, to whom she had lost an epic World Championship final, last year.

"I was leading by 2-3 points but she took a lead in the end and I was making simple errors and I was nervous but I managed to be patient and fought for each point and finished on top," Sindhu said.

World No 6 Sindhu has lost a lot of major finals, including the Rio Olympics, two World Championships in 2017 and 2018 and the Jakarta Asian Games, to settle for silvers in the last two years.

"I know I have won a lot of silvers but there is no pressure, I will just play the way I have played in the last four matches and if I can win this title it would mean a lot to me," Sindhu said.

Sindhu and Inthanon started on an equal note, splitting the initial 14 points. Sindhu tried to attack the long serves of Intanon, putting pressure on the Thai with her power-packed returns to lead 10-7. The Indian missed a couple of points before entering the break with a small 11-9 advantage.

Intanon quickly erased the deficit with a brilliant angled return at the net. While the Thai shuttler tried to target Sindhu's body, she also committed errors of judgement and went wide allowing Sindhu to stay a step ahead always.

Sindhu tried to put some lovely touch to her returns, leaving Intanon wrong-footed many times. She also unleashed some powerful smashes to trouble the Thai player.

Sindhu grabbed four game points when Intanon went wide and sealed it when the Thai player's angled return got buried in the net.

After the change of sides, Sindhu rushed away with the first four points but the deceptive Intanon narrowed down the lead to 5-6 with counter-attacking cross-court smash and then drew parity at 7-7 when Sindhu sent one wide.

But another shot going long and Sindhu was back in the lead and she made it 10-7 when the Thai player made another error in judging the shuttle on the line.

A 27-shot rally ended with a powerful smash from Intanon, who again levelled the scores at 10-10 and went to the break with a small 11-10 advantage when Sindhu committed two unforced errors.

Sindhu reeled off four points to again go into the lead but Intanon produced a superb net dribble and a precise smash at the deep corner to keep breathing down the Indian's neck.

Intanon equalled again when Sindhu went wide and then led 16-15 with another body smash.

Errors again caught up with Intanon as she missed the line and then went long as Sindhu led 18-16. But the Thailand shuttler again drew parity at 18-18 with another brilliant smash and a lucky net chord placed the game evenly-poised 19-19.

Intanon unleashed a superb cross court smash to move to a game point advantage. Sindhu responded with her trademark smash before hitting one out as it was advantage Intanon again.

An angled backhand return at the nets helped Sindhu make it 21-21 and she immediately grabbed her first match point with another smash.

Intanon saved it with another smash at the deep forehand corner and shot to lead when Sindhu found the net. But she stumbled on two unforced errors to hand Sindhu the match point. Sindhu converted it with a smash from near the net following a fierce rally.