PARIS — Carlos Alcaraz's hopes of finishing the season as the top-ranked player took a hit after a 6-3,6-4 loss to qualifier Roman Safiullin in the second round of the Paris Masters on Tuesday.

In his return from injury, Alcaraz dropped serve four times and made 27 unforced errors compared to 21 by the former world No 2 junior.

"I didn't feel well, you know, in the game," Alcaraz told a news conference. "I think I didn't move well. In the shots, I think I had a good quality of shots. But, you know, physically, in terms of movement, I have to improve a lot."

The Spaniard was knocked out in the fourth round of the Shanghai Masters nearly three weeks ago and withdrew from the Swiss Indoors in Basel because of a left foot injury and muscle fatigue to his lower back.

Alcaraz leads the ATP Tour with six titles this year, but hasn't lifted any trophy since Wimbledon. He seems to be running on fumes lately because of his demanding style of play.

"Probably because the season has been so, so long," Alcaraz said. "That probably affects my game."

The second-seeded Alcaraz and Safiullin traded breaks in the third and fourth games. Alcaraz struggled to find his range and dropped serve at 4-3, with a poor game that included a double fault and two unforced errors. Safiullin hit a service winner and two backhand winners to grab the opening set.

Play was briefly interrupted in the beginning of the second set to switch off a vivid pink light under the roof of the arena that troubled the players when they were tossing the ball to serve.

Alcaraz rifled two consecutive return winners to break for a 3-1 lead only to see Safiullin break back in the next game with a forehand pass. Alcaraz dropped his serve again in the seventh game, hitting a forehand long at the end of a long rally. Safiullin converted his second match point when Alcaraz sent a forehand return wide.

"Even if he's not in the best shape, it's tough to beat him, so I'm really happy that I made it," Safiullin told the ATP.

Last season, Alcaraz became the youngest year-end No 1 in the history of the ATP rankings. He is looking to achieve the extraordinary feat of claiming two year-end No 1 finishes at only 20.

Top-ranked Novak Djokovic had racked up 500 more points than Alcaraz this season before the Paris Masters.

Djokovic won't be able to clinch the year-end No 1 spot in Paris since Alcaraz still gets 10 points for his second-round defeat.

There are 1,000 points for the Paris Masters winner and 1,500 points for a perfect run at the ATP Finals.

Daniil Medvedev also has an outside chance of finishing the season as the No 1 player.

Before the Paris Masters, Djokovic, Alcaraz, Medvedev, Jannik Sinner and Andrey Rublev had already qualified for the ATP Finals, the season-ending tournament for the top eight players on tour that will be played in Turin from Nov 12-19.

Meanwhile, Alexander Zverev and Hubert Hurkacz stayed in contention for the three remaining spots at the ATP Finals by advancing to the second round.

The 10th-seeded Zverev rallied past qualifier Marton Fucsovics 4-6,7-5, 6-4, while Hurkacz overcame Sebastian Korda 6-3, 6-7 (6), 6-3.

Djokovic warmed up by playing doubles with Kecmanovic on Tuesday. The Serbian pair beat Gonzalo Escobar and Aleksandr Nedovyesov 6-4, 6-2 in the first round.

Agencies via Xinhua