MIAMI (AFP) - Third-seeded Andy Murray shook off a sluggish start to defeat Austrian Dominic Thiem 3-6, 6-4, 6-1 on Wednesday and reach the semi-finals of the Miami Masters.

Murray, a two-time winner at Crandon Park, was facing the 21-year-old for the first time.

After dropping the first set, the Briton lifted his game in a combative second set, breaking twice to square the match and cantered home in the third after an hour and three-quarters.

Murray, who won his 500th match in the previous round, sealed the win on his first match point with a service winner to boost his Miami record to 26-7.