Novak Djokovic has revealed his intense frustration with his game at the moment after he lost to Aslan Karatsev in Belgrade as he prepares for the French Open.
The world number one was expected to thrive at his home event, which is organised by his brother, but came up short in what amounted to a big surprise at The Novak Tennis Centre.
It was the second shock defeat in as many weeks for Djokovic, who was also beaten in the last 16 of the Monte Carlo Masters by Britain’s Dan Evans.
Opinion: Djokovic facing big decision, but don't make him the villian again
Djokovic praised Karatsev after what he said was a forgettable evening and spoke in candid fashion about what he needs to do ahead of Roland Garros.
"Hats off to Karatsev, he was bold and deserved to win," Djokovic told a virtual news conference.
"I will probably not be able to recollect all the memorable rallies in this match because I lost. I am not happy with my performance, I put up a fight but he delivered great shots every time he needed to.
- 'Djokovic is more obsessed' with Slams tally, 'well done for him' - Nadal
- 'The best victory of his career' - Nadal congratulates Evans after Brit shocks Djokovic
"I was unlucky at times, it all came down to one or two shots but I had too many ups and downs throughout the match," the 18-time Grand Slam champion added.
Roland Garros is the main goal but I need to play better if I’m thinking about doing something there. I have a lot of work ahead of me.
Karatsev said: "At the Australian Open in Melbourne I felt like I was playing against a wall but this is a different surface and I was focused.
"You have to put in like 200 per cent to beat this guy, it’s like playing against a wall. This is definitely [the biggest win of my career], it’s the world No 1.
"I’m really happy, I put everything on the court. The match was long. I’m really happy with my performance today."
The 27-year-old Russian saved 23 of 28 break points in the match and the number three seed will now face Matteo Berrettini in Sunday’s final after the Italian defeated Taro Daniel of Japan in three sets.
Djokovic has entered the main draw for the Madrid Open but has not confirmed whether he will play at the event, which will feature 13-time French Open champion Rafael Nadal.
'Evans defeat one of the worst I can remember' - Djokovic
- - -
Watch the 2021 French Open live on Eurosport, eurosport.co.uk and the Eurosport app.
Djokovic 'will need to be double vaccinated' - Australian Immigration Minister
Unvaccinated players 'unlikely' to be allowed to play at Australian Open