March 24 (Reuters) - World number two Jannik Sinner fought back in the second set against American Alex Michelsen to seal a 7-5 7-6(4) victory and reach the Miami Open quarter-finals on Tuesday, extending his record run of consecutive sets won at ATP Masters 1000 events.
Sinner edged a tight opening set before facing a sterner test in the second, where he trailed 5-2 as Michelsen raised his level from the baseline.
The Italian fought back to force a tiebreak, which he closed out to maintain his perfect
record against the American and further stretch his unprecedented run of straight sets won at Masters 1000 level to 28.
"I felt like the serve helped me quite a lot today, especially in important moments and in the tiebreak, so I'm happy about that," Sinner said in his on-court interview.
"I know that if I want to go far in this tournament, I have to improve from the back of the court. Tomorrow is a day off, which helps me and I will try to find good rhythm in the practice session. Then we'll see how things go."
Sinner also reached his 20th Masters quarter-final, while he kept alive his bid for a rare "Sunshine Double" after lifting the title at Indian Wells earlier this month without dropping a set.
The 24-year-old could become the first man since Roger Federer in 2017 to win both U.S. hard court Masters events in the same season.
(Reporting by Janina Nuno Rios in Mexico CityEditing by Toby Davis)
