'I'm used to that whenever I'm playing these days'

Nick Kyrgios has laughed off a Cincinnati crowd that never stopped cheering for the defeated Rafael Nadal in their quarter-final on Saturday.

The Australian shocked the American crowd as he upset Nadal, who will replace Andy Murray as world No.1 on Monday, with a 6-2 7-5 victory.

Nadal was broken in his first two service games, leading those in attendance to roar for every point he won until the end of the first set.

But Kyrgios held strong, overcoming some jitters late in the second set to pick up a second win over the Spaniard in four meetings.

"This is what you dream about as a little kid, playing against the greatest players of all time," he said in an on-court interview.

"I'm pretty sure 95 per cent of the crowd were going for him. I'm kind of used to that whenever I'm playing these days. I'm just happy to get the win."

Kyrgios has had a mixed reaction in the United States, having been booed and jeered during a match against Roger Federer in Miami earlier this year.

It did not affect his play this time, however, as the 22-year-old added to his remarkably positive record against some of the best in the world, which includes two wins from two over Novak Djokovic.

But he is often criticised for tanking against lower-ranked players or retiring after aggravating an injury - his hip and shoulder have caused concern in matches this year - only to commit against the best of the best.

"The problem for me is trying to bring it on an everyday basis," he told reporters later.

"Say the centre court of Lyon with, like, 15 people against Nicolas Kicker earlier this year. I lost. Tonight I'm playing Rafa and I win. These matches aren't the problem. It's those (low-profile) matches for me."

Kyrgios also opened up about the off-court problems he has faced in recent times, including the death of his grandfather.

That saw the 22-year-old barely pick up a racquet in the lead-up to the French Open as he spent time with family in Canberra.

"In the last couple of months I had a rollercoaster of scenes," he said.

"Ever since Davis Cup (in April), I had such a big high. Obviously my grandpa passed away. Had some off-court issues. My head's been all over the place.

"I have just been going through a load of s***, sorry for cussing, but a load of stuff that's distracted me from just trying to play some tennis, and hopefully I'm just trying to get on the right track again."

He will face Spanish veteran David Ferrer on Sunday morning for a place in the final against John Isner or Grigor Dimitrov.

Kyrgios has met Ferrer just once in his career - a three-set loss in the first round of the 2013 US Open.

And he hasn't forgotten it.

"He beat me four years ago, probably when I was about 15 kilos heavier, a bit out of shape," he said.

"That was my first US Open so hopefully things can go a little different."

with Omnisport