World number two Carlos Alcaraz crashed to a 6-3 6-4 loss to Russia's Roman Safiullin in the second round at the Paris Masters on Tuesday.
The Wimbledon champion looked off the pace as he made his return to action after withdrawing from the Swiss Indoors championships last week due to injury, losing the first set despite earning an early break.
The 20-year-old Spaniard seemed to recover as he again broke the 45th-ranked Saffiullin's serve early in the second set to take a 3-1 advantage.
But the 26-year-old Russian kept his foot on the gas to earn the biggest win of his career.
The result was another blow to Alcaraz's hopes of gaining ground on Novak Djokovic in the ATP rankings, with the top-ranked Serbian next in action on Wednesday against Argentina's Tomas Etcheverry.


Clinical Sinner holds off wildcard Jodar to reach Madrid Open semis
LIV Golf touts 'strong momentum' despite New Orleans postponement
Baptiste's variety drags Sabalenka out of comfort zone in Madrid shock
FIFA to increase financial distribution to all 48 World Cup teams by 15%
Sabalenka stunned by Baptiste in Madrid Open quarter-finals
