John Isner, Miami Open
Apr 1, 2018; Key Biscayne, FL, USA; John Isner of the United States kisses the Butch Buchholz championship trophy after his match against Alexander Zverev of Germany (not pictured) in the men's singles final of the Miami Open at Tennis Center at Crandon Park. 6-7(4), 6-4, 6-4. USA TODAY Sports / Geoff Burke

American journeyman John Isner stunned World No. 5 Alexander Zverev 6-7 (4), 6-4, 6-4 to capture the Miami Open Masters on Sunday (Monday AEDT). It was 32-year-old Isner's first taste of an ATP Masters 1000 title.

Isner was evidently getting tired during the second set until a sudden boost of energy helped him break Zverev in the ninth game to go up 5-4. It was the turning point in the match as Zverev seemed primed to win the tournament at Key Biscayne and potentially move into a World No. 3 ranking behind Rafael Nadal and Roger Federer.

"I couldn't have scripted this. (When) I came into this tournament, I had won one ATP match all year and was playing very poorly. I won my first match (here) in three sets and that's how tennis goes - you start to gain a little confidence and the next thing you know things start to roll your way," the 14th seeded Isner said during his courtside interview, via Reuters.

Isner, who had lost in three previous Masters 1000 finals, will now become the highest-ranked American at World No. 9 when the new ATP rankings are released on Monday (Tuesday AEDT). Isner had also lost in five previous Masters 1000 semi-finals, including two last year.

"It was unique, that someone I'm so much older than (Zverev), and had practiced with when he was a kid, is now one of the best players in the world. I never imagined I could play him in a match like this. It's crazy for Sasha and I to share the court in the last singles final of the tournament," Isner said after becoming the first American man to win the Miami Masters since Andy Roddick in 2010.

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