'The greatest non-grand slam match ever played'

Nick Kyrgios's loss to Roger Federer in the Miami Open semis was overshadowed by poor crowd behaviour, but the match itself was of incredible quality.

According to Kyrgios's former coach Todd Larkham, the three-set thriller was the best game of tennis he's ever seen, outside of a grand slam.

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Kyrgios continued his incredible form by pushing the Swiss Maestro to his absolute limits, falling two points short of victory as Federer prevailed 7-6 (11-9), 6-7 (11-9), 7-6 (7-5).

Mutual respect. Image: Getty

Larkham coached Kyrgios for almost a decade before they split in 2014, and recently said the match was played at an "incredibly high level" from start to finish.

"The match with Nick and Federer was possibly one of the greatest matches outside a grand slam that I've ever seen," Larkham said.

"There was nothing in it, only a couple points, and Nick has shown he can match it with anyone now which is awesome.

"They both played an incredibly high level of tennis, Nick is a great competitor but so is Federer and it came down to just a few points in the tiebreak where Fed came up with the shots."

Kyrgios will now suit up in green and gold as Australia battles the United States in this weekend's crunch Davis Cup clash.

Larkham believes Kyrgios's willingness to lift for his country will prove the difference.

"Nick is in better form and he didn't play last time so I think we've definitely got a better chance," Larkham said.

"It was pretty close in Melbourne, Isner played well on the grass and his serve was unbreakable, but I think on the hard court it will be easier to break him, so we're definitely in a better spot there.

"Based on form Nick would be the slight favourite to win his singles matches, he's been playing better than the other guys, but Jack Sock has been playing well this year.

On Tuesday Kyrgios said he's never felt more focused in his tennis career and puts it all down to ongoing support from his Davis Cup teammates.

While he hasn't appointed a coach just yet, Kyrgios was relishing being back with the Davis Cup team, saying it brought the best out of him.

Federer celebrates his victory. Image: Getty

"I prefer the team environment, I love being around these guys, I love training with them and I love being on the sidelines watching them compete," he said.

"I love everything about this team event and Davis Cup."

The 21-year-old has made three semi-finals and one quarter-final in his last four ATP Tour events.

He also beat world No.2 Novak Djokovic twice in two weeks.

It is a big turnaround after Kyrgios dramatically crashed out of the Australian Open in the second round, admitting he needed to start taking his tennis more seriously.

"Where I'm at mentally, I'm just competing for every point and playing hard and I haven't really had that mindset before," he said.

"I'm feeling motivated and I want to get out there more. I want to compete and I want to play.

"I'm probably in the best place I've ever been in."