MELBOURNE (Reuters) - Roger Federer made hard work of reaching his 27th consecutive grand slam quarter-final at the Australian Open on Sunday but it looked like a short shift after Francesca Schiavone's titanic tussle with Svetlana Kuznetsova.
French Open champion Schiavone took a gruelling four hours and 44 minutes to edge her Russian friend 6-4 1-6 16-14 in a Hisense Arena thriller and claim a place in the last eight after the longest women's grand slam singles match in the modern era.
Maria Sharapova would happily have played on longer in her fourth round match against Andrea Petkovic but the in-form German sent the former champion and world number one tumbling out of Melbourne Park 6-2 6-3 in just 79 minutes.
Defending champion Federer took his career record to 10-0 over Spain's Tommy Robredo but his 6-3 3-6 6-3 6-2 victory was not without its problems.
In hot sun on Rod Laver Arena, the 16-times grand slam champion raced through the first set in 32 minutes without losing a point on his serve.
Errors started creeping into the 29-year-old's game in the second -- his forehand particularly wayward -- and he conceded an unlikely break to allow Robredo to level the contest.
Federer was in no mood to give Robredo any more encouragement, however, and he upped his aggression level to keep his bid for a fifth Australian Open title on track.
"I'm happy I'm still alive and going strong in the tournament, said Federer, whose run of successive quarter-finals now betters American Jimmy Connors' previous mark.
"It's a tough match. I knew Robredo was going to come out and hit a lot of loopy shots and make me earn it. He wasn't going to just give it to me ... I was able to battle through," added Federer who will play close friend and fellow Swiss Stanislas Wawrinka in the last eight after he battered American eighth seed Andy Roddick.
Another mediocre effort from Federer.
One thing is for sure he's going to have to play spectacular if he wants to get past Wawrinka in the quarters the way he's playing (wow I never thought I would say that!).
"The other Swiss" has some major skills who would have thunk it!.
Federer is going to have his work cut out for him.
I'm both excited and in complete freak-out mode about the next match. Let the nail biting commence!.