Isner stops Del Potro's run to set up Miami final against Zverev

John Isner ended Juan Martin Del Potro’s 15 match unbeaten streak on Friday night with a 6-1 7-6 victory to reach the final of the Miami Masters. Isner served 13 aces during the 83 minute match and will play the fourth seed Alexander Zverev in Sunday’s final.

John Isner has played in four Masters finals. Reuters/Geoff Burke

"I have played a lot of big matches and not been able to get such a good start but I am playing some of the best tennis I have played in such a long time," Isner said.

"I started the tournament well and I have improved with every game. I am super fresh and ready to go for the final."

Del Potro’s run of wins has furnished him with titles at the Mexican Open and the Indian Wells Masters. But the fifth seed looked visibly sapped during his semi-final against the big serving American.

"I don't want to think about tennis right now," said the 29-year-old Argentine. I will miss a few tournaments to get ready for the French Open. We will come up with a schedule for the clay court season.

"I will go home now, spend time with friends and not talk about tennis for the next few weeks."

Isner, seeded 1'th, won 83 percent of points on his second serve and the 32-year-old will play in his fifth final at a Masters tournament which are ranked second behind the Grand Slam events in terms of prestige final and ranking points.  

Del Potro added: "When John plays like that, he's one of the toughest guys on tour to beat."

Zverev took 88 minutes to dispatch the Spaniard Pablo Carreno Busta 7-6 6-2 and book his ticket for the final.

The 20-year-old German will be seeking his seventh career ATP title and first of the season.

"Every day I want to serve big," he said. "I was very fortunate to win the first set and then I found my game in the second set."