TURIN, Italy, Nov 11 (Reuters) - An off-colour Carlos Alcaraz suffered a shock 6-1 7-5 defeat against Norway's Casper Ruud in his opening match at the ATP Finals as the Spaniard's hopes of winning the year-end title for the first time suffered a blow on Monday.

Carlos Alcaraz opened his account at the ATP Finals on Wednesday with an entertaining 6-3, 7-6 (10/8) win over Andrey Rublev, while Casper Ruud missed an early chance to reach the semi-finals after losing in straight sets to Alexander Zverev.

Carlos Alcaraz opened his account at the ATP Finals on Wednesday with an entertaining 6-3, 7-6 (10/8) win over Andrey Rublev, while Casper Ruud missed an early chance to reach the semifinals after losing in straight sets to Alexander Zverev.

Over his last 10 tournaments, Alcaraz has won 83.3% of his service games and 35.8% of his return games. Over his last 10 tournaments, Ruud has won 25.7% of his return games and 80.1% of his service games.

Norway's Casper Ruud eased to a straight-sets victory over Carlos Alcaraz on Monday as the Spanish star's bid for a maiden ATP Finals title got off to a poor start.

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

Spain's Carlos Alcaraz made light of feeling under the weather as he dispatched Russia's Andrey Rublev in impressive fashion to revive his ATP Finals hopes on Wednesday. The Spanish four-times Grand Slam champion has been suffering with respiratory issues in Turin and wore pink nasal tape against Rublev but enjoyed a resounding 6-3 7-6(8) victory.

I was really calm," Alcaraz said. “I just focused on my game and what I have to do and forgetting I'm not feeling well." Alcaraz scribbled 'Valencia' on a TV monitor after his victory to show support for compatriots hit by recent floods.