Sebastian Korda explains how he beat John Isner

The 20-year-old Sebastian Korda is through to his first ATP semi-final in Delray Beach following a 6-3, 4-6, 6-3 triumph over world no. 25 John Isner in an hour and 51 minutes.

Korda saved five out of six break points and secured three breaks to make the difference, playing well behind Isner's first serve. The youngster moved in front with a break at 3-3 in the opener and grabbed another in game nine to complete the set in style. Raising his level, John played better in set number two and used one loose service game of his opponent to level the score and force a decider.

Nothing could separate them in the first seven games before Korda placed a backhand winner that pushed him 5-3 up. Serving for the victory, Sebastian saved three break points in game nine and moved over the top with a service winner.

"I was super happy with how I played that whole match. I mean, John played an incredible first three points. The way he played those, I was like, 'Too good.' I couldn't do anything. He came to the net and played big balls. I just stuck with it; I got a little bit more aggressive. In the end, there was a lot of stress in that last game, so I let it go with the roar. My dad is all for me.

As long as I'm happy, he's happy. Whenever I'm on the court, my head is pretty clear, and I'm a super positive guy, so I'm always in the moment. There are very few times you'll see any emotion come out of me that's negative. I worked a lot on that during this break, and it's paying off right now," Sebastian Korda said.