Rafael Nadal of Spain returns a shot during his men's singles tennis match against Stanislas Wawrinka of Switzerland at the Shanghai Masters tennis tournament in Shanghai, Oct 11, 2013. [Photo/Agencies]

SHANGHAI - World No 1 Rafael Nadal battled past 8th seed Stanislas Wawrinka of Switzerland to set up a Juan Martin del Potro semifinal clash at the Shanghai Masters tennis tournament while defending champion Novak Djokovic will face Frenchman Jo-Wilfried Tsonga in the other one.

Nadal had to take the second tiebreak in two days as the Spaniard needed one hour and 14 minutes to close the opening set and after that the world No 1 never looked back, winning the quarterfinal at 7-6(10), 6-1 on Friday.

He will face up against 6th seed Del Potro of Argentina, who beat 15th seed Nicolas Almagro of Spain 6-3, 6-3 in an earlier quarterfinal.

Del Potro is one match win away from qualifying for the Barclays ATP World Tour Finals after he reached the semifinals.

He beat Almagro for the second time in as many weeks with a 6-4, 6-3 win in 72 minutes. The pair met in the Rakuten Japan Open Tennis Championships semifinals last week.

The 25-year-old Del Potro won 85 percent of his first service points and committed just eight unforced errors.

"I played very well today, very solid," said del Potro, who has overcome a fever.

"I played aggressive. I hit my forehand very well. I like the way I played today. I just want to keep improving [and] keep going far in this tournament."