(CNN) -- Andy Murray and Novak Djokovic maintained their title charges in Tokyo and Beijing with quarterfinal victories by contrasting routes Friday.
Murray was extended to three sets in beating Switzerland's Stanislas Wawrinka for this 50th win on the ATP Tour this year and the 10th in a row.
Djokovic needed less than an hour to beat Austria's Juergen Melzer 6-1 6-2 at one of his favorite venues.
He won the China Open title in 2009 and 2010 but did not defend his crown last year.
The Serbian, beaten by Murray to lose his U.S. Open crown last month, converted all four of his break points and fired 12 aces in a near flawless display.
"The serve was great tonight. It's one of the best serving matches I have had in my career, so that's a positive sign. I will try to keep on going," he told the official ATP Tour website.
Djokovic will play Germany's Florian Mayer as he bids to reach his ninth final on tour this year.
Spain's Feliciano Lopez will play third seed Jo-Wilfried Tsonga of France in the other semifinal Saturday.
In the women's draw, Li Na beat defending champion Agnieszka Radwanska of Poland 6-4 6-2 to secure reach the semifinals and seal her place in the season-ending WTA Championships in Istanbul.
Top seed Victoria Azarenka and Maria Sharapova are also in the last four.
World No.3 Murray looked set to wrap up an easy win over Wawrinka, one of his victims as he won Olympic gold in London, when he took the first set with two breaks of service.
But Wawrinka hit back to force a decider before the Britain pulled away again with two more breaks to wrap up the match in two hours 50 minutes.
He will face Milos Raonic of Canada for a place in the final.
The Canadian, beaten by Murray in the fourth round at the U.S. Open, saved a match point before beating Janko Tipsarevic 6-7 6-2 7-6.
"I'll try to do what I did in New York. I got a lot of returns in play. Once I was in the point, I was able to dictate a lot of them so I'll try and do the same tomorrow," Murray said as he looked forward to their last four clash.
Home hopes were kept alive by eighth seed Kei Nishikori, who became the first Japanese player to reach the semifinals of their home open.
He upset second seed Tomas Berdych 7-5, 6-4 Friday and will now take on Marcos Baghdatis, who beat qualifier Dmitry Tursunov 6-2 6-4.