Wow! What a game.

A rare error from Murray as a double fault at 15-15 gives Dimitrov a sneaky peek at the break. And another loose serve sticks it right under the Bulgarian's nose.

That's two break points to the Bulgarian, who sees one slip through his grasp after a tremendous point which sees both players dashing around the court. But Dimitrov snaffles the second as he screams up at his box with pure pleasure.

Misslad:, external Absolutely amazing. Really can see the work with Amelie paying off. She's really influenced Andy's already brilliant game #bbctennis

Johnjackknife:, external What ever Murray has done in the winter I need to get some he's coasting through the Australian open like a freight train #bbctennis

Image source, Getty Images

Breathless stuff in the Rod Laver Arena. Not least for Grigor Dimitrov, who stays within one on the scoreboard by serving out to love. The Bulgarian mutters to himself as he takes his seat and gulps a huge intake of water. He knows he has got work to do.

Murray retreats to the baseline, inviting Dimitrov to go on the attack. But then the Briton springs out of the traps like a hungry greyhound, pouncing on the ball to flick beyond the stranded Bulgarian after his cross-court return clips the net. That's 30-15.

One return goes awry as Dimitrov squares, but two thunderous serves leave the Bulgarian all limp wristed in his attempts to return.

Stunning stuff from Andy Murray!

The British number one digs out his third backhand winner - this one as clean as a whistle - to go 30-15 ahead. His next cross-court effort is not quite as slick, but he earns another break point by drilling a firm forehand at the Bulgarian's feet.

Dimitrov didn't have his dancing shoes then, and he can't get his feet right again as he plants a return into the net. Murray jigs in delight.

Can Murray follow suit and cling on to his serve? Yes he can!

The Briton is forced to jump over the hurdle of deuce but blasts down a second serve on game point to move level. Dimitrov face palms himself.

Image source, EPA

Let's see what Dimitov can dig out of the drawer in response.

He pins Murray back on the ropes before the Briton bounces back into the ring - Rocky Balboaesque - with a brilliant forehand punch of his own for 15-15.

However, Dimitrov reasserts his control to hold serve.

Andy Brown:, external Wow, Murray just went right into Dimitrov's back pocket and stole that set!#bbctennis #ausopen

Mike Willis:, external Dimitrov would've won that set against 99% of other players. Quality stuff from both guys! #BBCTennis #AusOpen

Greg Edwards:, external This is a completely different Murray to last year. Much more aggressive and playing closer to the baseline! Good work Mauresmo! #bbctennis

Piers Newbery
BBC Sport at Melbourne Park

"Murray has played few better sets than that since he won Wimbledon, weathering a brilliant 16 minutes from Dimitrov and wrestling control with some magnificent returning in particular. Shouts of "Come on Andy!" much more in evidence now."

"Oooh," gasp the crowd as a wild Dimitrov return flies well past the whitewash. The Bulgarian shakes his head in disbelief and disgust. And then he can only do the same again as Murray, with two set points in the bag, fires down an ace on the first opportunity.

What a turnaround from Murray!

Image source, Getty Images

From 3-0 down to serving for the set! No wonder Andy Murray looks pleased with himself.

The Briton blows his first chance of a break at 40-30 by finding the net, which leads to a look to the heavens and few unrepeatable mutterings under his breath. Deuce.

But Murray's world is suddenly a better place within seconds. He pounces early on a loose Dimitrov serve, then finishes the job with a forehand winner as Dimitrov is left scrambling at the other side of the court.

Goran Ivanisevic
2001 Wimbledon champion on BBC Radio 5 live sports extra

"Andy is really pumped, ready and feels he is ready to win a Grand Slam. He's fit, hitting the ball great and the draw is good for him."

Sarah Alonze:, external Never underestimate Murray. He might not have come out of the starting blocks like Dimitrov, but he's built for the long haul.

Murray looks relaxed as he realigns his black t-shirt after holding to love within about 90 seconds. A blink-and-you'll-miss-it sort of game.

Dimitrov started like an Intercity 125 express train, but has been slowed down by controller Murray.

The Briton senses another chance to break his opponent's serve but goes long after an intense rally for 30-40 and then can't return a thunderous Dimitrov serve.

That's a big notch on the scoreboard for the Bulgarian.

Andy Murray is finding more rhythm than a Strictly Come Dancing star now. The Briton spanks down three aces to leave Dimitrov floundering - and the scoreboard looking healthy. Len Goodman would be giving him a 'nine' if he was marking that game...

Piers Newbery
BBC Sport at Melbourne Park

"Murray has pummelled away at the Dimitrov backhand, clearly a gameplan, and for 20 minutes it wasn't working. It took that breathtaking backhand winner for Murray to unsettle the Bulgarian, and his vociferous knot of supporters, and a flashing return to get the break back. Meanwhile, the crowd roars at the changeover as news filters through that Kyrgios has forced a fifth against Seppi."

Image source, Getty Images

Home hope Nick Kyrgios is into a final set against Italian Andreas Seppi after winning a tie-break in the fourth set.

Backed by a boisterous Australian following, Kyrgios took the breaker 7-5 against Roger Federer's conqueror.

The winner will face off against Murray or Dimitrov in the last eight.

"Come on!" shouts a fist-clenching Andy Murray. Exactly what the tennis doctor ordered.

The British number one produces a moment of brilliance when he needs it - a flick of the left hand pings the ball over the net and across court at the acutest of angles - to go 40-30 ahead. Even Dimitrov smiles wistfully.

And the Bulgarian can't recover in the next point as Murray breaks back.

James Stevenson:, external What a start from Dimitrov. This is Murray's sternest test so far for sure. 10 minutes for the first 3 games. Ouch!