John Isner boosted Team World's hopes in the Laver Cup on Saturday after beating Alexander Zverev 7-6, 6-4, 10-1.
Zverev pipped Isner to the post to take the first set for Team Europe by 7-6, after a tie-break which saw the World No. 6 take the American apart 7-2.
In the second set the pair were again evenly matched. Neck and neck at 4-4, an error by Isner allowed Zverev to stave off disaster momentarily, but the German quickly returned the favour with a misplaced ball to give Isner the break he needed and go on to win 6-4.
In another tie-break to decide the outcome of the match, Isner, ranked 20th in the world, made light work of Zverev, gaining seven points before he allowed his opponent the opportunity to claw one back.
However, it wasn't enough and he won the tie-break 10-1 to win overall.
Speaking after the match, Isner said: "I wasn't making any in roads on his [Zevrev's] serve at all... He was the better player for 85% of that match."
Speaking of defeats by Zverev and Federer in previous matches, he said: "Maybe we're turning the tables just a little bit," adding, "Team World is in this and we're here to win."
Roger Federer takes on Nick Kyrgios on Saturday afternoon.