Madison Keys kept her hopes of reaching the last four at the WTA Finals alive with a scintillating 6-1 6-4 victory over Dominika Cibulkova in Singapore.
Sixth seed Keys was beaten in straight sets by Simona Halep in her opening match and would have been eliminated with defeat to Cibulkova - now on the brink of bowing out herself - on Tuesday.
However, the American maintained her flawless record against the seventh seed, winning their fourth encounter without dropping a set, though her hopes of qualifying may rest on a positive result against Angelique Kerber in her final Red Group outing.
Keys' power proved too much for Cibulkova in the first set, her searing forehand helping open up a 4-1 advantage after which the Slovak called for her trainer.
The world number seven closed out the opening set in just 22 minutes, hitting 16 winners while Cibulkova committed just two unforced errors.
Cibulkova appeared rejuvenated at the start of the second but, after saving a pair of break points in game five, a double fault gifted Keys an advantage she would not surrender - a sublime cross-court forehand off a low ball down the line from Cibulkova typifying her dominant display.
Keys  bt Cibulkova  6-1 6-4
Keys - 26
Cibulkova - 6
Keys - 6
Cibulkova - 0
BREAK POINTS WON
Keys - 3/6
Cibulkova - 0/0
FIRST SERVE PERCENTAGE
Keys - 59
Cibulkova - 68
PERCENTAGE OF POINTS WON ON FIRST/SECOND SERVE
Keys - 86/60
Keys - 57
Cibulkova - 39