(Reuters) - World number three Carlos Alcaraz is unlikely to be at his best for Wednesday's ATP Finals match against Andrey Rublev as the four-times Grand Slam champion continues to struggle with illness, the Spaniard's coach Juan Carlos Ferrero said.

Carlos Alcaraz struggled with a stomach issue and looked far from the player who won two Grand Slams this year in losing to Casper Ruud 6-1, 7-5 at the ATP F

You can watch coverage of this week's ATP finals on the Tennis Channel. Two group matches will be played each day, with the semi-finals then taking place on Saturday, Nov. 16 and the finals on Sunday, Nov. 17. The Tennis Channel is available on several platforms including Fubo TV, Sling, DirecTV and YouTube TV.

Carlos Alcaraz had his drop shot working and overcame physical issues to claim a 6-3, 7-6 victory over Andrey Rublev at the ATP Finals

Carlos Alcaraz struggled with a stomach issue and looked far from the player who won two Grand Slams this year while losing to Casper Ruud 6-1, 7-5 at the ATP Finals on Monday.

Carlos Alcaraz struggled with a stomach issue and looked far from the player who won two Grand Slams this year in losing to Casper Ruud 6-1, 7-5 at the ATP Finals. It marked Ruud’s first victory over Alcaraz in five career meetings,

Casper Ruud stuns an out-of-sorts Carlos Alcaraz at the ATP Finals, before Alexander Zverev beats Andrey Rublev.

Carlos Alcaraz had his drop shot clicking and it helped him overcome physical issues to claim a 6-3, 7-6 (8) victory over Andrey Rublev at the ATP Finals on Wednesday.