Carlos Alcaraz looked little like the player who won two Grand Slams this year in a 6-1, 7-5 loss to Casper Ruud at the ATP Finals on Monday.

Alcaraz, who won the French Open and Wimbledon titles this year ... Sinner beating debutant Alex De Minaur and American ...

Alcaraz won the French Open and Wimbledon this year to boost his career total ... Top-ranked Jannik Sinner and U.S. Open ...