Serena Williams and Jelena Jankovic made it through to the quarter-finals of the Western and Southern Open in Cincinnati

Script: Top seed Serena Williams took on Italy's Karin Knapp in round three in Cincinnati.

Williams, still recovering from her shock defeat to Swiss teenager Belinda Bencic in the semi-finals of last week's Rogers Cup in Toronto, swept through the first set, winning 75 per cent of the points.

Knapp managed to hold serve twice in the second set and Williams comfortably made it through to the last eight.

She'll play sixth seed Ana Ivanovic, who beat Sloane Stephens 2-6, 6-4, 6-1.

Ivanovic's Serbian compatriot Jelena Jankovic also booked her place in quarters.

Up against the number eight seed, Karolina Pliskova, Jankovic broke serve twice in the opening set to take it 6-2, but Pliskova converted the only break point in the second set to level.

Pliskova opened up a 4-2 lead in the decider, but Jankovic won five of the following six games and after more than two hours on court, closed out a 6-2, 3-6, 7-5 victory.

Slovakian qualifier Anna Karolina Schmiedlova.