Novak Djokovic moved closer to a place in the semi-finals of the ATP Finals as the world number one dispatched Alexander Zverev 6-4, 6-1 on Wednesday. Djokovic is chasing a sixth ATP Finals title and his first in the prestigious season-ending event at London's O2 Arena since 2015. In his 11th appearance at the Finals, the Serb will be guaranteed to reach the last four for the eighth time if John Isner beats Marin Cilic or if Cilic defeats Isner in three sets later on Wednesday.

Djokovic, who beat Isner in his opening group-stage match, has enjoyed a remarkable renaissance in the second half of 2018 and lifting the trophy on the banks of the River Thames would be the perfect way to finish his year. Djokovic faces Cilic in his last group match on Friday, while Zverev, who defeated Cilic to kick off his Finals campaign, takes on Isner. The 31-year-old was assailed by claims he had lost his hunger for success and was past his best after injury and personal issues threatened to derail his career in 2017.