MIAMI - Andy Murray outlasted an ailing Matteo Berrettini 4-6 6-3 6-4 on Wednesday to move into the second round of the Miami Open where he will again try to do something he has not done this season -- win two consecutive matches.

After starting the campaign losing the opening contest in his first four tournaments, including the Australian Open, the three-times Grand Slam winner has now advanced to the second round in his last four events but each time was unable to clear the next hurdle.

The victory added another small milestone to the 36-year-old Scotsman's career as he became the third active player with 30 wins at the event, behind only Novak Djokovic (44) and Rafa Nadal (40).

"It was obviously a great win for me," said Murray, who wrote the message, 'Life in the old dog yet :)' on the courtside TV camera lens after his match.

"I started off a little bit slow, but I do think I played pretty well from the middle of the first set until the end of the match."

Murray got off to a sluggish start against Berrettini, who looked sharp and energised in a dominant opening set despite seeing his first tour-level action since the U.S. Open following an injury layoff.

The momentum took a dramatic shift in the second set, however, as the 27-year-old Italian began to struggle while Murray found his rhythm to power ahead 5-2.

Berrettini's next service game saw the Italian double over and stumble as he appeared close to fainting. The tournament doctor quickly arrived and play was delayed for four minutes while Berrettini received treatment and had his blood pressure checked.

When action resumed Berrettini held serve before Murray served out the set to level the match, with the Italian leaving the court during the changeover for more checks.

Sensing an opening, Murray pounced and broke Berrettini at the first opportunity to get in front 2-0.

Murray, twice a champion in Miami, would need that break as Berrettini battled on gamely, holding serve the rest of way but unable to convert any of his three break chances in the final set.

Murray sealed victory with a backhand winner down the line, which was immediately followed by a defiant fist pump.

"I created a lot of opportunities and he was struggling for a little bit at the end of the second and beginning of the third," said Murray, who next faces Argentine Tomas Martin Etcheverry.

"I capitalised on that and got off to a quick start in the third. I served it out well in the end." REUTERS