NICK KYRGIOS insists he has the "tools" to knock his friend Andy Murray out of Wimbledon on Centre Court today, even though the famous SW19 arena is the Scot's "backyard".

The 21-year-old Australian, who booked his place in today's fourth round encounter by completing a 6-3, 6-7 (2), 6-3, 6-4 win against Feliciano Lopez on 'People's Sunday', was defeated by the World No.2 on all three of the other slams during 2015 but feels that the grass courts of Wimbledon offer him the best chance of victory.

The controversial figure from Canberra feels that Novak Djokovic's defeat to Sam Querrey has opened up this year's Wimbledon and includes himself in the list of players who now think they can win the title.

While the pair meet frequently at Playstation and on the practice courts, Kyrgios was victorious when the pair met at the Hopman Cup, the early season exhibition event in Brisbane, back in January

"As soon as Novak loses, you look at Andy and you look at Federer's eyes light up," said Kyrgios.

"They think that their chances probably doubled. I think a lot of people in the locker room now believe they can win it.

"If the stars align and they're playing well, there's a lot of people that can go get it. I rarely walk into a tournament and don't think I can win it.

"I've definitely got the tools to beat him," he added. "The last couple times I played Andy, I lost to him at the US Open in four sets, then I played him in the Hopman Cup and beat him there.

"So I definitely feel like he's beatable. He's only human. But at the same time he's a great player."

Aside from that Hopman Cup meeting, Murray has lost only one set to Kyrgios in Grand Slam play and the Scot has had the more coMfortable tournament thus far.

While Novak Djokovic lost to Querrey out on Court No.1, the Scot has been kept on Centre Court all fortnight long, having the luxury of getting his matches finished without dropping a set. Kyrgios, by contrast, will be playing for the fourth successive day by the time he walks out on court.

The Aussie has played just once on Centre Court previously, his last 16 victory against Rafa Nadal.

"It's a huge advantage, I think," said Kyrgios. "But, you know, he deserves it. He's obviously comfortable there - it's like his backyard. But it's the same dimensions as any court I've played on since I was a little kid. This is probably my best surface, my best chance to beat him."

Kyrgios apologised for any offence caused when he was heard using the word 'retard' as he shouted in the direction of his box.

"I know some people can obviously get offended by that," he said. "I'm not meaning to be rude or disrespectful at all."

Murray, who sees a little of his former self in Kyrgios, spoke out in the player's defence and said he is over-scrutinised by the media.

"He is good fun," added the Scot. "He chats to everyone and I have never really seen him in a bad mood off the court.

"Obviously on it, like I have many times and loads of players have in the past, he has made mistakes, and done stuff that is wrong. Sometimes in the press he does get a bit of a hard time and he goes on the defensive a little bit when maybe he doesn't need to but I can understand that as well.

"When you see what some of the other players have done here – players that are better than him and won a lot more than him – the coverage they get for destroying a racket is much less than he does for saying to the umpire: 'You have done a bad job' or 'You were terrible today', whatever. But because it is him, it is a bigger story then they ask about it in the press."

Djokovic's shock exit on Saturday has had echoes of Murray's 2013 win, where he met Jerzy Janowicz of Poland in the semi-final rather than Roger Federer or Rafa Nadal, and Roger Federer.

The Swiss legend who faces Stevie Johnson today, was quick to place extra pressure on the Scot. "Of course it affects every player here that Novak is out," said Federer. "Now all that pressure shifts to a lot of other guys, particularly Murray, maybe myself and others. It’s an opportunity and that can also play tricks on some players’ minds. So you just need to focus on your next match."