Gael Monfils raised alarm bells around his form just days before he stunned Carlos Alcaraz at the Cincinnati Open.

The veteran Frenchman came from behind to upset the No. 2 seed 3-6 7-6(4) 6-4 in a match halted by an overnight rain delay.

Before beating the four-time Grand Slam champion, Monfils claimed that his training sessions were “catastrophic” and felt something was missing.

Monfils was on a three-match losing streak coming into Cincinnati, having suffered back-to-back first-round exits from the Olympics and the Canadian Open. Ahead of the tournament, his outlook was understandably bleak.

“I’m training, but it’s catastrophic,” the 37-year-old told L’Equipe. “Now, I’m going to go back to training to do my fifth hour of the day, it’s hard but it’s not enough. I’m giving it my all, but the sensations aren’t there. There’s something missing”

While Monfils was giving it his all, he admitted that it was difficult to have confidence without the right foundations in practice. He continued: “Without the right feeling in training, it’s difficult in matches.

“The atmosphere can go crazy, and because I’m well trained, I can respond. But it’s still better to come away from a training session feeling good. It allows you to go onto the court, for the match, feeling good. I say catastrophic because I want better.”

The world No. 46 managed to prove himself wrong in the first round when he took on newly-crowned Canadian Open champion Alexei Popyrin. It was the boost he needed going into his third career meeting with Alcaraz.

The Spaniard took the first set when they started the match on Thursday evening. Monfils led by a mini-break in the second set tiebreak when the rain came and their match was pushed back by a day.