Andy Murray rallied to prevent a fifth set being played as he defeated Grigor Dimitrov 6-4 [5]6-7 6-3 7-5 in the last 16 of the Australian Open in Melbourne.

Murray found the contest tough going in the opening stages as he surrendered to a 3-0 deficit, but the Scot rallied to break Dimitrov and serve for the first set at 5-4.

The 27-year-old made sure of a set lead when he produced a crucial ace at 40-15 that flew past the Bulgarian, who had no answer.

Murray continued some fine play with the second set underway as he broke Dimitrov again to take a 2-1 lead, this time drilling a firm forehand into his opponent's feet.

Dimitrov soon broke back, however, as the scores were moved to 3-3, but it was not enough as the Scotsman pulled off another breathless game to break and establish his own serve to move into a position to take a two-set lead.

Murray was a little lacklustre on his serve and it appeared as if Dimitrov would come up with another break of his own, which he did to force a tiebreak for the second set.

The 23-year-old took advantage of his momentum to win the breaker and bring things level at one set each, having produced some powerful tennis from the baseline.

However, Murray produced a turning point in the match when he broke his opponent to make it 5-3 in the third and give himself the opportunity to serve for the set, a feat that the number six-ranked player achieved with relative ease.

Back came Dimitrov, though, and he notched some fine points on the forehand side to move to a 5-2 lead in the fourth, leaving Murray serving to prevent the game going into a nervy decider.

The Scot went one better as he rallied to break Dimitrov and move the scores to 5-4 and his resurgence continued as he brought things level with a telling backhand.

That shot was to prove pivotal as Murray confidently won the next two games, with the final victory coming off his own serve to seal things.