Angelique Kerber is just one win away from becoming world number one after getting past Simona Halep in the Western and Southern Open semi-finals.
The Australian Open champion claimed a 6-3 6-4 win in Cincinnati on Saturday to set up a meeting with Karolina Pliskova in the decider.
A victory for second seed Kerber would see her replace Serena Williams, sidelined with a shoulder injury, as world number one.
Not even a rain delay could stop Kerber, who benefitted from a remarkable 50 unforced errors from Halep as the Romanian's 13-match winning run was ended.
There were numerous breaks of serve in the first set, but Kerber won three straight games from 3-3 - having given up a 3-1 lead.
Kerber rolled out to a 4-0 lead in the second set - a deficit Halep recovered from in her last-eight win over Agnieszka Radwanska - before closing out victory.
Garbine Muguruza's wait for another WTA final continues after she was beaten in straight sets by Pliskova.
The French Open champion has not featured in the final of a tournament since her victory over Serena Williams at Roland Garros, and Pliskova's 6-1 6-3 win continues that drought.
Fourth seed Muguruza struggled to hold her own serve in the opening set as Pliskova reeled off six games in a row, and any hopes Muguruza had of mounting a comeback were quickly dashed.
A break of Pliskova's serve in the fifth game of the second could not provide the spark she needed, and it had the opposite effect as the Czech sealed her place in Sunday's final - the 24-year-old finishing the match with 17 winners.