Paris (AFP) - World number one Carlos Alcaraz crashed out in the first round of the Astana Open on Tuesday, losing 7-5, 6-3 to Belgium's David Goffin.
US Open champion Alcaraz suffered his first straight-sets defeat since November last year as Goffin made the most of his second chance as a lucky loser.
Alcaraz, 19, was playing his first ATP tournament since his victory in New York that saw him become the youngest ever world number one.
He played in last month's Davis Cup, winning one of his two singles rubbers as Spain claimed a place in the quarter-finals.
Goffin only earned a spot in the main draw after the withdrawal of Danish teenager Holger Rune.He plays Frenchman Adrian Mannarino in the last 16.
"I always believe that I have the level to cause some trouble against those guys," said Goffin, a former top-10 player now ranked 66th.
"When you play against the world number one on a big stage, big crowd, the fire inside gives you so much power to play your best tennis because you don't have any choice.
"You have to fight and give your best and that was the case today.I always believed I had it and I am happy you can still it there."
It was 31-year-old Goffin's third win against a top-ranked player, having beaten Rafael Nadal in 2017 and 2020.
Unlike Alcaraz, third seed Stefanos Tsitsipas avoided an early exit as he eased past Mikhail Kukushkin 6-3, 6-4.
The Greek is hunting a third ATP title of the season.He reached 50 tour-level wins in 2022 after breaking Kukushkin once in each set.
"It was a great match from my side," said Tsitsipas, who goes on to face Italian qualifier Luca Nardi for a quarter-final place.
Karen Khachanov won on his first outing since reaching the US Open semi-finals, defeating American Maxime Cressy 6-4, 7-6 (7/3).
Daniil Medvedev plays Albert Ramos-Vinolas in the first round later on Tuesday.
Novak Djokovic is due to face Cristian Garin on Wednesday after winning the 89th title of his career in Tel Aviv last weekend.
