Alexander Zverev got the better of John Isner to book his place in the last four of the ATP World Tour Finals with a 7-6 6-3 win. The pair started the match as two of three players looking to book their place in the last four alongside Marin Cilic and the opening set was a predictably cagey affair.
Related: More To Come From Djokovic In London
After going with serve, a tie-break was required and it was Zverev who prevailed to take the lead, taking the wind out of the American’s sails with him arriving at the O2 Arena on Friday needing a straight-sets victory to progress.
The second set continued to be dominated by the pair’s fearsome serves but the German achieved the first break of the match to go 5-3 up in the eighth game.
He then held his nerve to seal a 7-6 6-3 victory and at 21, becomes the youngest man to reach the semi-finals since Juan Martin del Potro in 2009.
The world number five will face Roger Federer in Saturday’s semi-finals, with the closing match in Group Guga Kuerten between Cilic and Novak Djokovic on Friday evening now a dead rubber.