ATP Finals: Alexander Zverev is victorious in straight-sets win over Marin Cilic

Germany's Alexander Zverev comes through a tight match against Croatian Marin Cilic with a straight-sets win 7-6 (7-5) 7-6 (7-1) in his opening game of the ATP Finals at the O2 Arena in London.

READ MORE: Alexander Zverev punishes Marin Cilic with straight-sets win

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