Nick Kyrgios admits he meant to hit ball at Rafael Nadal in ill-tempered match

Nick Kyrgios confessed he was aiming to hit Rafael Nadal with the ball during a rally in their bad-tempered second-round Wimbledon encounter, which the Spaniard won in four sets.

The two have been locked in a war of words over the last few months, with Kyrgios trading insults with Nadal and his uncle Toni, and that threatened to spill out on to Centre Court in the Spaniard's 6-3 3-6 7-6 (5) 7-6 (3) victory.

There was almost a flashpoint in the third set when Kyrgios thrashed a forehand straight at Nadal, which he refused to apologise for and later said he did on purpose.

The Australian was perplexed by the notion that he should have said sorry, insisting that Nadal has enough money in the bank to be able to take a ball on his body while the Spaniard branded him "dangerous".

"Why would I apologise?" Kyrgios said. "I didn't hit him. Hit his racket, no? Why would I apologise? I won the point.

"I don't care. Why would I apologise? I mean, the dude has got how many slams, how much money in the bank account? I think he can take a ball to the chest. I'm not going to apologise to him at all.

"I was going for him. I wanted to hit him square in the chest. Like, he's got decent hands."

That was not the first time that Kyrgios had aimed to hit the ball as hard as he could at Nadal and several flew wildly out of court.

The Spaniard, aiming for a third Wimbledon crown, said: "The history of this sport is about respect and is about playing fair during the whole time.

"I don't say Nick does this stuff to bother the opponent, but it is true that sometimes he's dangerous.

"When he hits the ball like this, is dangerous. It is not dangerous for me, it is dangerous for a line referee, dangerous for a crowd.

"When you hit the ball like this, you don't know where the ball goes.

"I know he's a big talented player, but I am a professional player too. I know when you hit this kind of ball, the ball can go anywhere.

"This time the ball went in, almost hit me, no problem. I am professional, so I know how to avoid this.

"But another one, the ball goes straight to the back. So (it would) have been a dangerous moment for the line umpire.

"That ball hits an eye or something like this, is a problem. That's it.

"Is not about that I am angry about him at all. It's about I want to play a match of tennis. Sometimes it is difficult."

It was a sub-plot of a thrilling match on Centre Court that had underarm serves, arguments with the umpires and some fabulous tennis.

One of the catalysts of the spat between the two players is Kyrgios' frustration at Nadal's speed of play, something that earned him a warning for venting at umpire Damien Dumusois, who he called a "disgrace".

He later added "terrible" to his description of the official.

Kyrgios added: "I'm serving, I'm like starting my routine. Rafa said, 'Stop'.

"The rule is like play to the speed of the server. Why do I have to wait for him to get into his rhythm every time?

"I got angry at the ref. He's like, 'No, I'll tell him what I want to tell him'.

"I was like, 'Oh, a little bit of a power trip there'. He obviously feels pretty important sitting up in the chair.

"He was just terrible. I thought the way he handled the match was just bad.

"I just don't think he was up to scratch today. That's most definitely not why I lost."