By Martyn Herman
LONDON (Reuters) - Roger Federer's immaculate Wimbledon continued as he moved smoothly into the quarter-finals for the 12th time in his career on Tuesday by outclassing Spaniard Tommy Robredo.
The Swiss, bidding for a record eighth title at the grassscourt slam, needed only one hour 34 minutes of sublime tennis to win 6-1 6-4 6-4 and avenge a humiliating defeat at the hands of Robredo at last year's U.S. Open.
All eyes have been on defending champion Andy Murray's regal progress through the draw so far this year but Federer again issued a reminder that, when his game is flowing there are few better sights in world sport.
Sunshine ushered in day eight of the championships and organizers sought to re-calibrate the men's and women's singles draws on a day usually reserved for the women's last eight.
Last year's runner-up Sabine Lisicki, a round behind after having to finish off third round opponent Ana Ivanovic on Monday, survived a shoulder injury scare to beat Kazakhstan's Yaroslava Shvedova 6-3 3-6 6-4.
The German 19th seed took a medical time-out in the middle of a game at 1-1 in the decider, having her shoulder massaged while lying on the turf, but recovered to reach the quarter-final for the fifth time in five visits.
Romania's "Miss Consistency" Simona Halep raced to a 6-3 6-0 fourth-round win over Kazakhstan's Zarina Diyas as she maintained her dazzling from in this year's slams.
The Wimbledon third seed reached the French Open final earlier this month and began the year with a quarter-final run at the Australian Open.
Lisicki said she hoped her shoulder would be in good enough shape to face Halep in Wednesday's quarter-finals.
Federer, also facing an unusually busy schedule at Wimbledon because of the rain that fell on Saturday and Monday, will be back on court on Wednesday with a quarter-final against fellow Swiss Stanislas Wawrinka.
On the day that Switzerland face Argentina in the World Cup last 16, Wawrinka beat a bad-tempered Feliciano Lopez 7-6(5) 7-6(7) 6-3, easing through without any major alarms.
Federer, yet to drop a set or a service game in his most impressive route to the quarter-finals since 2004, said it was a good time to be Swiss.
"For a small country we are doing well in sporting teams," he told the BBC.
"Hopefully our football team can beat Argentina later and it will be amazing to play Stan in the quarter-finals here because things like that don't happen too often in Swiss sport."
Later on Tuesday world No.1 Rafael Nadal is in fourth round action against Australian upstart Nick Kyrgios.
The women's quarter-finals also start with three Czechs in the last eight of a grand slam for the first time in the professional era.
Former Wimbledon champion Petra Kvitova, the sixth seed, faces Barbora Zahlavova Strycova, while Lucie Safarova is up against Russia's Ekaterina Makarova.
(Reporting by Martyn Herman; editing by Clare Lovell)