World number one Carlos Alcaraz suffered a shock defeat at the Paris Masters on Tuesday, falling to Britain’s unseeded Cameron Norrie in a three-set battle (4-6, 6-3, 6-4).

The loss ended the Spaniard’s formidable 17-match winning streak at the ATP Masters 1000 level. Alcaraz, who recently won his eighth title of the season in Tokyo, appeared off his game, committing 54 unforced errors during the match.

Norrie, ranked 31st in the world, rallied after dropping the first set to secure what he called the “biggest win of his career.” The victory, which took two hours and 22 minutes, marks his first-ever win against a reigning world number one.

“Massive victory, so big for me,” Norrie said after the match. “I have just tried to enjoy my tennis in the second half of the year and I was able to do that… especially against the most confident player in the world right now.”

This defeat is Alcaraz’s first loss before a tournament final since March and puts his year-end number one ranking at risk. Italy’s Jannik Sinner could claim the top spot if he goes on to win the Paris title.

Norrie advances to the third round to face either Valentin Vacherot or Arthur Rinderknech.