Zverev continued his impressive form against Alcaraz, who has struggled with a chest complaint during this tournament and once again wore a pink nasal strip to aid his breathing.

Seemingly still feeling the effects of that illness, Alcaraz was again off form but showed some fighting spirit to save seven break points in the first set, then two set points before Zverev superbly converted the third.

Zverev had four of those break points saved in the fourth game of the match, then had set point on Alcaraz's serve when leading 6-5, but hit a cross-court forehand long following an extensive rally. The Spaniard forced the tie-break but Zverev was once again able to get his nose in front.

After both produced superb shots during the tie-break including a terrific cross-court lob from Alcaraz Zverev managed the best to finally secure the set.

His third set point saw the German dig out an attempted Alcaraz winner with a brilliant half-volleyed pick-up near the net. Alcaraz spooned the returning volley wide and Zverev roared in celebration.

Zverev only needed to win that first set to guarantee his spot in the last four but he was determined to secure the win to get the top spot in the John Newcombe Group.

The break in the second set was easier to come by, as Alcaraz fired a straightforward volley into the net to give up the immediate advantage.

Wimbledon and French Open champion Alcaraz was clearly unhappy, the third seed loudly complaining to his team after falling 3-1 behind in the second set.

He psyched himself up enough to force two break points against Zverev at 3-2 the first the German had faced in the entire tournament but was unable to convert before Zverev saw out the match.