Seven-time Grand Slam champion Carlos Alcaraz suffered a shock 7-5, 7-6 defeat by unseeded Belgian Zizou Bergs in the Shanghai ‌Masters round of ⁠32 on Monday, a result that also confirmed Alexander Zverev as the ATP's year-end world ‌number one.

Fresh from defending ‌his Japan Open title with a ‌victory over Czech Jiri Lehecka and building momentum ‌after a lengthy wrist injury layoff, Alcaraz never found his rhythm in a scrappy two-hour, two-minute contest.

"It's a little disbelief and not feeling too much," Bergs, 27, said afterwards. "You're just really in the moment, being focused on the points you have to play," he added.

The second-seeded Spaniard, who ⁠was ‌sidelined for nearly five months before returning at the US Open in late August and reaching the quarter-finals, joined 24-times Grand Slam ‌champion Novak Djokovic and US Open runner-up Ben Shelton among the high-profile casualties at the ATP Masters 1000 event.

The upset also ensured that French Open and US Open champion Zverev, 29, will finish the season as the ATP year-end world ⁠number one, becoming the first ⁠German to achieve ⁠the feat.