Rod Laver Arena/Melbourne Park, Melbourne VIC 3000, Australia, 7 January 2016 | AAP

Nick Kyrgios made good on a promise to friends by beating world No.2 Andy Murray 6-4 7-6 (7-5) in Wednesday night’s Hopman Cup blockbuster at Perth Arena.

Kyrgios entered the match having lost all four of his previous matches to Murray, with three of those coming in grand slams last year. But with Murray battling a mystery leg injury, Kyrgios ran the two-time grand slam winner ragged during the clinical display.

“I actually did promise a couple of my friends that next time I played Andy, I was going to beat him,” Kyrgios said.

“He’s in the prime of his career. He’s been playing some great tennis. Every time I’ve played him I haven’t played bad

“He’s just a great player and today I knew what my game plan was going to be and how he was going to play.”

The tie between Australia Green and Great Britain was sent to a live mixed doubles after Daria Gavrilova failed to successfully serve for the win in her 6-7 (7-2) 6-2 7-5 loss to Heather Watson.

Gavrilova was up 5-3 in the third set, but the naturalised Australian lost the last four games in a match that lasted 165 minutes.

But Australia Green got there eventually, securing a 2-1 tie win after midnight with a 6-2 6-7 (7-0) 11-9 (match tiebreak) win in the mixed doubles.

The result means Australia Green will reach Saturday’s final if they can beat France on Friday night.

“It was a lot of fun. That match tiebreak was one of my favourite tiebreaks I’ve ever played,” Kyrgios said.

Murray appeared troubled by a right thigh injury during his singles loss.

But he played down the injury after the match.

“It was just the same thing as the other day,” Murray said.

“I’m still moving fine around the court, it’s just a little bit sore.

“I’ll be fine. No problem.”

Meanwhile, the world No.30 said his breakthrough win over Murray would give him a huge dose of confidence heading into the Australian Open.

“It doesn’t matter what type of match you’re playing, you always want to win,” Kyrgios said.

“One hundred per cent he wanted to win that tonight. I thought it was a good match.

“He’s a true champion. He’ll come back and I’m sure he’ll be ready, and he’s a strong contender for the Australian Open.”