Jannik Sinner began his tilt at a maiden Paris Masters crown which would return him to world number one with a 6-4, 6-2 win over Zizou Bergs on Wednesday, while reigning champion Alexander Zverev battled through a lengthy three-setter.

Following the surprise exit of world number one Carlos Alcaraz at the round of 32 stage on Tuesday, a maiden crown in the ATP 1000 event in the French capital would return Sinner to the summit of the world rankings.

But the Italian second seed showed no signs of feeling the weight of that pressure in his opening match at La Defense Arena -- the top eight seeds received byes through the first round.

"I'm very happy to come through the first match," Sinner said.

"I was very precise, and I also started off with a break straight away, which gives you a bit more confidence."

Four-time Grand Slam champion Sinner is known for his efficiency on-court and won through against 41st-ranked Belgian Bergs in one hour and 27 minutes without facing a single break point.

The 24-year-old methodically engineered breaks of his own early in both sets to seal his spot in the third round, where he will meet Francisco Cerundolo on Thursday.

Germany's Zverev battled past Argentine world number 49 Camilo Ugo Carabelli 6-7 (5/7), 6-1, 7-5 to open his title defence.

He will next take on Spanish 15th seed Alejandro Davidovich Fokina following his victory over Frenchman Arthur Cazaux.

A hardfought tie-break separated Zverev and Ugo Carabelli in the opening set, before the 28-year-old cruised through the second in 35 minutes.

It then seemed Zverev might follow Alcaraz in crashing out early at La Defense Arena when the third seed fell 1-3 behind in the decider.

But he hit back instantly on his opponent's next service game, before securing the crucial break at 5-5 to keep his title defence alive.

- Dimitrov withdraws -

Norwegian eighth seed Casper Ruud was felled in his opening match at the tournament by 50th-ranked German Daniel Altmaier 6-3, 7-5.

RTL

Alexander Zverev secured the crucial break at 5-5 in the third set against Camilo Ugo Carabelli to keep his title defence alive at the Paris Masters / © AFP

Former world number one Daniil Medvedev of Russia was given a walkover to the third round after Grigor Dimitrov withdrew with a shoulder issue.

The 34-year-old Bulgarian's return from a pectoral injury, which forced him to retire when leading eventual champion Sinner two sets to love in the fourth round at Wimbledon in July, unfortunately lasted only one match before his latest fitness set-back.

Italy's Lorenzo Musetti, who occupies the final qualification spot for November's ATP Finals in Turin, fell to a costly three-set defeat to compatriot Lorenzo Sonego.

Just behind Musetti in the race for Turin is Canadian ninth seed Felix Auger-Aliassime, who ground out a 5-7, 7-6 (7/5), 7-6 (7/4) win against France's Alexandre Muller.

Cousins Valentin Vacherot and Arthur Rinderknech opened the day's action in a repeat of their Shanghai Masters final from earlier in October.

And just like in China, it was the Monegasque Vacherot who claimed victory in three sets against the Frenchman. He will next face Alcaraz's British vanquisher Cameron Norrie.

A bad day for the host country was compounded when last hometown favourite standing, Corentin Moutet, went down in straight sets against fellow maverick and fiery character Alexander Bublik of Kazakhstan.

Afterwards on-court, Bublik quipped that the local-born Moutet would at least not have far to go now he was eliminated.

"I don't think it was personal," Moutet said. "Some people talk, some people don't. I guess he's part of the first category.

"He loves to verbally clash with people."

Russian 10th seed Karen Khachanov grinded past Brazilian teenager Joao Fonseca 6-1, 3-6, 6-3 and will meet Australian sixth seed Alex de Minaur in the round of 16 on Thursday.