Grand slam tennis champions Petra Kvitova and Svetlana Kuznetsova have been knocked out of the US Open, while Rafael Nadal breezed into the fourth round in New York.
81st-ranked US wildcard Alison Riske did for Czech seventh seed Kvitova while 27th-ranked Russian Kuznetsova also lost an error-riddled match in straight sets to Italy's Flavia Pennetta, ranked 83rd.
Nadal's closing in on a potential showdown with Roger Federer, the Spanish great stretching a career-best hardcourt win streak to 18 matches as he easily saw off Croatian Ivan Dodig.
Nadal now faces Phillip Kohlschreiber for a place in the quarter-finals, after the German veteran eliminated the last great American hope in the men's draw, knocking out big John Isner in four sets - Jack Sock was knocked out by Serb Janko Tipsarevic, leaving the unfancied Tim Smycek the final shot for the host nation on the men's side.
Women's second seed Victoria Azarenka and Serbia's Ana Ivanovic battled their way into the last 16, while also through to the fourth round are Spanish fourth seed David Ferrer and 10th-seeded Canadan Milos Raonic.
