Del Potro too strong for Roanic after first-set blip

Juan Martin del Potro came from a set down to beat Milos Raonic and book a place in the semifinals at the Miami Open.

Del Potro dominated two tie-breaks to secure a 5-7, 7-6 (7/1), 7-6 (7/3) victory.

Raonic, the world No 25, took the first set 7-5 after breaking in the 12th game of the set.

The pair were both strong on serve in the second as it went to a tie-break, but the Canadian conceded four mini-breaks as Del Potro took the set 7-6 (7/1).

The third set started with four games which went against serve, and again went to a tie-break, in which Del Potro broke three times to win 7/3.

Meanwhile, American John Isner progressed to the semi-finals with a comfortable straight sets victory over Chung Hyeon.

World No 17 Isner needed just an hour and nine minutes to complete a 6-1, 6-4 success over his South Korean opponent.

The 32-year-old 14th seed produced a serving masterclass, winning 31 of his 32 first-serve points and holding 21-year-old Chung’s only break point to set up a last-four meeting with Del Potro. Seven-time Grand Slam winner Venus Williams was knocked out in the quarter-finals of the women’s draw by qualifier Danielle Collins.

American Collins, 24, won 6-2, 6-3 and will now face Jelena Ostapenko.