Rafael Nadal defeats Stan Wawrinka to advance to semifinal in Shanghai

Rafael Nadal of Spain celebrates after defeating Switzerland's Stanislas Wawrinka during the singles quarterfinal match of the Shanghai Masters tennis tournament at Qizhong Forest Sports City Tennis Center, in Shanghai, China, Friday, Oct. 11, 2013. Nadal won 7-6, 6-1. (AP Photo/Eugene Hoshiko) (The Associated Press)

Serbia's Novak Djokovic celebrates after defeating France's Gael Monfils at their singles quarterfinal match of the Shanghai Masters tennis tournament at Qizhong Forest Sports City Tennis Center, in Shanghai, China, Friday, Oct. 11, 2013. Djokovic won 6-7, 6-2, 6-4. (AP Photo/Ng Han Guan) (The Associated Press)

Rafael Nadal and Novak Djokovic overcame tough challenges in their quarterfinals at the Shanghai Masters on Friday and moved a step closer to a possible showdown in the final.

Top-ranked Nadal saved three set points and finally closed out a 20-minute tiebreak in the first set against Switzerland's Stanislas Wawrinka before winning 7-6 (10), 6-1.

Djokovic, the defending champion, needed nearly 2 ½ hours to rally past France's Gael Monfils 6-7 (4), 6-2, 6-4.

Djokovic and Nadal improved to a combined 20-0 record against the pair.