Angelique Kerber took a step closer to world number one and reached the US Open quarter-finals for just the second time with a win over Petra Kvitova.
The German star eased into the last eight with a surprisingly comfortable 6-3 7-5 victory at Arthur Ashe Stadium on Sunday.
Kerber and Czech Kvitova had split their previous eight meetings, but the Australian Open champion proved too good in New York.
With it, the world number two moved closer to being top of the WTA rankings.
Reaching the quarter-finals at the year's last grand slam for just the second time and first since 2011, Kerber will be number one if Serena Williams fails to reach the final.
After trading breaks with Kvitova in the first set, Kerber won four of the last five games.
Both players squandered opportunities in the second before Kerber broke at the perfect time, a Kvitova double fault gifting her victory in the 12th game.
Next up for Kerber is Roberta Vinci, the Italian who was runner-up at the tournament last year.
Kerber  bt Kvitova  6-3 7-5
Kerber - 8/8
Kvitova - 32/43
Kerber - 0
Kvitova - 0
BREAK POINTS WON
Kerber - 4/8
Kvitova - 1/3
FIRST SERVE PERCENTAGE
Kerber - 65
Kvitova - 55
PERCENTAGE OF POINTS WON ON FIRST/SECOND SERVE
Kerber - 73/50
Kvitova - 76/29
Kerber - 71
Kvitova - 60