London - Agnieszka Radwanska booked her spot in the Wimbledon quarter-finals with a 7-5, 6-4 win over former world number one Jelena Jankovic on Monday.
The Polish 13th seed defeated the Serbian 28th seed - who knocked out defending champion Petra Kvitova in the third round - in an hour and 43 minutes.
Radwanska, the 2012 Wimbledon runner-up, faces Madison Keys of the United States, the 21st seed, in Tuesday's quarter-finals.
Jankovic lost her cool with the umpire towards the end of the match, telling him: "We're humans here.
"Well done. I don't want to speak to you."