Federer glides into last eight.

ROGER Federer drew on past experience during his victory over Robin Soderling as the second seed continued to make his mark on Wimbledon.

The five-time champion fired down 23 aces as he battled past the Swede 6-4 7-6 (7/5) 7-6 (7/5) in the fourth round in what was a repeat of the recent French Open final.

It was the 11th meeting between the two and Federer has yet to be beaten, dropping just one set to Soderling back in 2005 in Halle.

And the Swiss admitted he was able to put his knowledge of the world No.12 to good use on Centre Court.

"When you play a player like Soderling, who you've already beaten ten times in the past, it just shoots through your mind," said Federer. "All the information is right there stored somewhere.

"I was expecting more baseline play, for instance. I think you prepare particularly well for these kind of matches. He's got nothing to lose. Grass is more dangerous than clay, that's why I knew there was danger all over.

"If I was able to serve well and play well I knew I had a good chance because I've got some confidence against him." Federer's next challenge is against Ivo Karlovic, who knocked out seventh seed Fernando Verdasco 7-6 (7/5) 6-7 (4/7) 6-3 7-6 (11/9) on Court One.

The 6ft 10in Croatian will be a different prospect for Federer, and the world No.2 admitted: "He's not to be underestimated." Novak Djokovic could be Federer's opponent in the semi-finals if both players get that far. The Serbian comfortable beat Israel's Dudi Sela 6-2 6-4 6-1 yesterday..