(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.

On Monday, Casper Ruud rolled over Carlos Alcaraz in the first round of the ATP Finals. After losing in straight sets to Ruud, Alcaraz gave three excuses for his poor play. One of the most important reasons was his health.

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