Stanislas Wawrinka has described Kei Nishikori as a "great shot-maker" ahead of their quarter-final meeting at the Australian Open.
The defending champion beat Spain's Guillermo Garcia-Lopez in four sets to set up a match with the fifth seed, who knocked him out of last year's US Open.
The Swiss told reporters: "I've practised with him before the tournament. He's a great shot-maker.
"It doesn't matter where he is on the court, he is taking the ball really early so it's tough to play against him, he doesn't give you too much time.
"But if I can play heavy, if I can play my game, then that makes it tough for him to take the ball early."
Nishikori is into the last eight in Melbourne for just the second time in his career after beating David Ferrer earlier.