Croatian Marin Cilic beat American John Isner, coming from a set down, and achieved his first victory at the ATP Finals in London on Wednesday.

With the presence of the winner of the 2016 tournament, Britain's Andy Murray in the stands, Isner won the first set, which sent Novak Djokovic directly to the semi-finals. But Cilic took the next two to win 6-7, 6-3, 6-4 in two hours and 14 minutes.