Roger Federer knows he is in for a tough time in his scheduled US Open quarter-final against Robin Soderling.
The second seed moved into the last eight with a 6-3 7-6 (7/4) 6-3 win over Jurgen Melzer, ensuring he has still not lost a set at Flushing Meadows this year.
Next up is fifth-seed Soderling, who came from a set down to beat Spain's Albert Montanes 4-6 6-3 6-2 6-3.
Federer leads Soderling 12-1 head-to-head but lost their last match at the French Open this year, ending his run of 23 consecutive Grand Slam semi-finals.
Having had that result, Federer knows his opponent will be wanting more of the same.
"I expect it to be really tough, especially now that he's gotten a taste of how to beat me," said Federer.
"It's up to me to clean up my game and put in a good performance.
"He's been able to string together a few good years now on the tour. Before he was very good already, but he was a bit up and down. Maybe that's also maybe why his ranking was a bit lower.
"Now he is playing really well.
"Little things can have a huge impact - just growing up, too.
"It took me a long time to figure out that staying calm was going to be better for my game than not. I only realised that at about 20 years old."
As for his own plans against Soderling, Federer was clear.
"Like against any big server you try to read the serve, get into good baseline rallies, try to move him around, just play a solid match and have no hiccups on your own serve.
"I've been able to do that 12 times out of 13.
"So it's a matter up to me now if I can do it again."