Andy Murray through to Australian Open quarter-finals

Andy Murray extended his streak of consecutive grand slam quarter-final appearances to 16 with a rollercoaster victory over Grigor Dimitrov in the Australian Open. Murray looked set to be dragged into a decider when Dimitrov led 5-2 in the fourth set, but won the next five games to complete a 6-4 6-7 (5/7) 6-3 7-5 success in just over three and a half hours.

The match started on Sunday evening but fittingly stretched into the first hour of Australia Day (January 26) and Murray will now look to improve on his perfect 10-0 record against Australian players at tour level when he takes on home favourite Nick Kyrgios for a place in the semi-finals.

The 19-year-old had earlier come from two sets down to beat Andreas Seppi, who caused the shock of the tournament by knocking out Roger Federer in the third round, 8-6 in the fifth set.

Meanwhile 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 one of the eight. That’s the most important thing, no? Arriving here after losing in the first round of Qatar, not playing matches for the last seven months, to have the chance to be in quarter-finals again here is a very positive thing for me.

“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 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 Andy Murray, will provide an effective scouting report on Nadal, adding: "He is very good on that. He knows how to put up the plan before the match and how to prepare the player. That's what I was looking for and what I needed."

The match with Tomic was played on Margaret Court Arena and the Australian admitted he was amazed not to have played any of his four matches on Rod Laver Arena, the equivalent of Centre Court at Wimbledon.

“I think the scheduling was like ridiculous this year. Not just from my side, but for many players,” Tomic said. “I don’t know who was in charge of the schedule. Really, some of the matches I saw it was just like, ‘Wow.”’

There was better news for the home fans when teenager Nick Kyrgios staged a brilliant comeback to beat Andreas Seppi in five sets and become the first Australian man to reach the quarter-finals since Lleyton Hewitt in 2005.

Seppi had caused the shock of the tournament by knocking out Roger Federer in the previous round and carried on where he left off on Hisense Arena, winning the first two sets 7-5 6-4.

Kyrgios took the third set 6-3 and saved a match point in the fourth before winning it in a tie-break to force a decider which he eventually won 8-6 to send the partisan crowd wild – so much so that play was temporarily halted on the adjacent Rod Laver Arena due to the noise.

“This is incredible,” Kyrgios said in an on-court interview. “I drew on my experience from Wimbledon last year, coming back from two sets down against (Richard) Gasquet. I knew I had the legs to do it.”