Tomas Berdych came out on top against Jo-Wilfried Tsonga in their Shanghai Masters quarter-final clash on Friday, a battle between two of the leading contenders to reach the World Tour Finals.
The Czech fourth seed won 6-3, 7-6 (7/4), grabbing a crucial break against the powerful Frenchman in the first set and winning the second set tie-break to set up a semi-final clash against either Novak Djokovic or Tommy Haas.
With four berths still up for grabs at next month's elite eight-man showpiece in London, Berdych, 27, is sixth in the Race to London while Tsonga, also 27, is in eighth spot.
World number one Roger Federer, Djokovic and Shanghai Masters defending champion Andy Murray have already qualified, along with the injured Rafael Nadal.
Also in action in the last eight in Shanghai on Friday, Murray faces the Czech Republic's Radek Stepanek, Djokovic plays German veteran Haas and Federer goes head-to-head with 10th seed Marin Cilic of Croatia.
Federer's win on Thursday over Davis Cup team-mate Stanislas Wawrinka guaranteed him a record 300th week as world number one when the next rankings are published on Monday.
Haas, 34, who reached a best of number two in the world, is one victory away from reaching 500 singles match wins.