Rafael Nadal: History counts for nothing against Tomas Berdych, he's a great player

Rafael Nadal insists his amazing record against Tomas Berdych will count for nothing when the pair clash in the quarter-finals of the Australian Open.

Nadal had to save six break points in the opening set of his fourth-round clash with Kevin Anderson before easing to a 7-5 6-1 6-4 victory, while Berdych saw off home hope Bernard Tomic 6-2 7-6 (7/3) 6-2 on Sunday.

Third seed Nadal has an 18-3 career record against Berdych, who won three of their first four meetings but has lost the last 17 in a row.

'It doesn't matter what happened in the past. It is a different story this time,' Nadal said. 'Different moment for me, different moment for him. The way we arrive to that match is not going to affect what happens in the match. I'm sure of that.

'He's a great player. I have success against him, but I have the chances to lose against him. I remember in 2012 I had a very, very tough match against him here (in the quarter-finals). I was close to being two sets to love down. He's a player that is top level.'

Nadal admitted he thought of quitting during his second-round match with American Tim Smyczek on Wednesday, the Spaniard suffering from dizziness and nausea as he fell two sets to one behind.

However, the nine-time French Open champion dug deep to win in five sets and looks to be working his way back to form and full fitness after the latter half of 2014 was ruined by a wrist injury and appendicitis.

The 28-year-old continues to play down his chances of winning a second Australian Open title, but added: 'It's very special to be in the quarter-finals after a tough period of time for me, it's a fantastic result.

'I am not a person that I am happy like this and that's it. I try to play better and better every day.

'If that happens, I hope to keep having chances for the next match. But today is a day to be happy the way that I improved my level of everything, all the things I have to do on court. Today I was much closer (to) what I have to do to try to have success.'

Berdych, who lost to eventual champion Stan Wawrinka in the semi-finals here last year, has yet to drop a set but admitted he would still need 'something extra' against Nadal.

'I'm feeling very good,' the 29-year-old said. 'It's been a great, great run so far. I just put myself in the best possible position right now.

'I'm going to have to add something extra again. That's how the tournament is developing, just move forward, just be ready for it.'

Berdych hopes new coach Dani Vallverdu, who formerly worked with Britain's Andy Murray, will provide an effective scouting report on Nadal, and added: 'He is very good on that.