GENEVA, Switzerland — World No. 1 Novak Djokovic admitted he was "worried" about his French Open title defense after falling to 44th-ranked Czech Tomas Machac in the Geneva semifinals on Friday.

Djokovic went down to a 6-4, 0-6, 6-1 loss having taken a late wildcard into the Swiss clay-court tournament in a bid to reverse an alarming dip in form ahead of Roland Garros, where the 24-time Grand Slam champion has won three times.

"Of course, I'm worried. I haven't been playing good at all this year," said 37-year-old Djokovic.

"I've had some good matches here and there, but it is what it is. You have to accept it. I don't consider myself a favorite there. I'm going to take it match by match and see how far I can go."

The Serb will head to Roland Garros, where he faces Frenchman Pierre-Hugues Herbert in the first round having won no titles this year, his first such dry spell since 2018.

Djokovic, bidding to reach his first final of the season, received a medical timeout at the end of the first set and revealed he had been suffering a stomach complaint.

While in Geneva, Djokovic became only the third man after Jimmy Connors and Roger Federer to rack up 1,100 tour wins.

However, even that will not ease the worrying fact that Djokovic is just 14-6 this year with runs to the semifinals at the Australian Open and Monte Carlo Masters his best performances.

Djokovic, bidding for his fourth French Open title, could lose his No. 1 ranking in Paris to Jannik Sinner and must reach the semifinals to have any chance of keeping the Italian at bay.

Machac, competing in his maiden tour-level semifinal, rallied from a breakdown in the first set on Friday and after failing to win a game in the second powered back in the third set.

"I'm looking forward to playing in a final for the first time," said Machac, who will face two-time champion Casper Ruud or Italian Flavio Cobolli in the title match on Saturday.