Kerber through to US Open last eight

Best week of my life – Queen’s Club champion Lopez

Second seed Angelique Kerber made the most of an error-riddled performance from Petra Kvitova to secure a 6-3, 7-5 victory in the fourth round of the US Open.

The Australian Open champion only managed eight winners to the 32 of Kvitova, but with the Czech struggling to 42 unforced errors that was all that was required.

Kerber, who will face Roberta Vinci in her first quarter-final appearance at Flushing Meadows since 2011, claimed two breaks of serve in each set to the one of Kvitova who struggled horribly on her own serve.

The two-time Wimbledon champion's woes were surmised by the final point of the match where she failed to defend a match point after succumbing to her seventh double fault. To make the moment even worse for Kvitova, she mixed in two lets, failing to find the target with four attempts.

The result brings down the curtain on a disappointing grand slam campaign for 14th seed who had failed to make it past the third round in the year's first three grand slams.

Kerber, meanwhile, is enjoying something of a golden season, having claimed her maiden grand slam title in Melbourne while also reaching the final at Wimbledon and securing silver at the Rio Olympics. Should the German win at Flushing Meadows she could unseat Serena Williams as the world's top-ranked player, a feat that seemed near-impossible 12 months ago.

Joining Kerber and Vinci in the quarter-finals are Caroline Wozniacki who downed eighth seed Madison Keys, and Anastasija Sevastova, who was a surprise victor over a fatigued Johanna Konta.