Instead of a big headline Williams vs. Robson matchup, Kanepi will now face Lisicki in the quarterfinals.
Former champion Petra Kvitova, last year's runner-up Agnieszka Radwanska and No. 4 David Ferrer all avoided upsets to advance, as did sixth-seeded Li Na of China.
Juan Martin del Potro, playing with his left knee heavily taped after a scary fall in the previous round, beat Andreas Seppi 6-4, 7-6 (2), 6-3. He said his knee was "really painful" but that he hopes it will be better by the time he plays fourth-seeded David Ferrer on Wednesday.
Ferrer overcame another slow start to beat Ivan Dodig of Croatia 6-7 (3), 7-6 (6), 6-1, 6-1. Having trailed twice in the previous round before winning in five sets, Ferrer struggled initially to create opportunities on Dodig's serve and was two points from going two sets down against the Croat. But he dominated the final two sets, breaking Dodig five times and clinching the match with a forehand winner.
Despite Williams' loss, there's still an American woman in the quarters after Sloane Stephens beat 19-year-old Monica Puig of Puerto Rico 4-6, 7-5, 6-1.
On a busy day at Wimbledon with every round-of-16 match to be played, Kvitova was the first to reach the last eight, beating Carla Suarez Navarro of Spain 7-6 (5), 6-3. She will play Kirsten Flipkens of Belgium, who reached her first career Grand Slam quarterfinal by ousting Flavia Pennetta of Italy 7-6 (2), 6-3 — a year after her ranking plummeted to 262nd because of injuries.
Poland will send two men into the quarterfinals for the first time after 24th-seeded Jerzy Janowicz and 130th-ranked Lukasz Kubot each won five-set matches.
The big-serving Janowicz outlasted Jurgen Melzer 3-6, 7-6 (1), 6-4, 4-6, 6-4, while Kubot defeated Adrian Mannarino 4-6, 6-3, 3-6, 6-3, 6-4. They'll play each other Wednesday with the winner becoming the country's first Grand Slam semifinalist.
In other results, Verdasco beat Frenchman Kenny De Schepper 6-4, 6-4, 6-4, and 15th-seeded Marion Bartoli ousted Karin Knapp of Italy 6-2, 6-3. Radwanska rallied to beat Tsvetana Pironkova of Bulgaria 4-6, 6-3, 6-3.