Wimbledon 2011: Roger Federer and Novak Djokovic win

Roger Federer and Novak Djokovic remain on course to meet in the Wimbledon semi-finals after both winning through to the last eight.

Six-time champion Federer, seeded third, saw off Mikhail Youzhny 6-7 (7-5) 6-3 6-3 6-3 to set up a quarter-final meeting with Jo-Wilfried Tsonga.

Third seed Djokovic extended his 2011 win-loss record to 47-1 with a 6-3 6-3 6-3 victory over Michael Llodra.

He will next play Australian qualifier Bernard Tomic, who beat Xavier Malisse.

Federer lost the first set after being 4-2 up in the tie-break but normal service was resumed when he levelled the match on his fourth set point.

He raced into a 5-1 lead in the third set and, although Youzhny pegged him back to 5-3, the Swiss finished strongly to extend his advantage.

Federer broke his opponent in game one of the fourth set but the Russian 18th seed had immediate break-back points to restore parity.

However, he was unable to take advantage and Federer sealed his place in the last 16 on his third match point to book a tie with Tsonga, who was a straight-sets winner over seventh seed David Ferrer.

"It was a tough first set to lose but he did well and it was a good match," Federer told BBC Sport.

"When you lose the first set in a Grand Slam it is always somewhat tricky mentally so you have to divert from your original plan and all those things can add up to something dangerous.

"I was happy I was playing well in the second set but it was getting quite dark and there were some drops in the air. I didn't know what time we could play to but in the end the sun came out and it was perfect.

"I'm playing well it's always somewhat tricky coming on to Court One as I am not used to the surroundings. It just feels a touch slower and sounds a little different but still I was happy with the match and I am looking forward to a tough battle with Tsonga."

Djokovic opened against Llodra with a quickfire hold to love and followed it up with a break of serve when the Frenchman sent down an untimely double fault.

It was not long before the second seed had powered his way to 4-1 and, despite missing two break points in game six, he wrapped up the opener with only 28 minutes on the clock.

Llodra, making his last-16 debut and - at 31 - the oldest play left in the draw, gave a far better account of himself at the start of the second set with some excellent variety.

But Djokovic broke his resistance in game six, held to love for 5-3 and then snapped up the double-break at the end of a brilliant game nine to extend his advantage.

Llodra faced two break points in game one of the third set, but served his way out of trouble and remained in contention until game eight.

He then failed to convert a straightforward smash to give Djokovic a 40-15 lead and he duly completed the break at the second time of asking with a sliced forehand winner.

Djokovic flicked a forehand winner up the line to seal victory with a love hold.

"It's never easy, I can't say it was easy, I had to earn my points and played well," said Djokovic, who returned to top form after smashing a racquet during his third-round win against Marcos Baghdatis.

"I increased my level of performance from two days ago - I served well and returned better. I'm very happy and now looking forward to the next challenge."

That challenge comes in the form of the 18-year-old Tomic, who continued his stunning run at SW19 with victory over Malisse.

Djokovic knows what awaits him as he has been practising with Tomic of late.

"I have only nice words about him," added the two-time Grand Slam champion, who did not face a single break point and remains on course for a potential semi-final tie with Roger Federer.

"It will be a great match for both of us. He's a youngster coming up with incredible talent, he's going to be a top player one day.

"He's been beating good players comfortably in this tournament and it will be tough."