Novak Djokovic is through to the fourth round of the French Open but boy did he make things look difficult.The defending champion needed five sets to defeat world No.41 Diego Schwartzman 5-7 6-3 3-6 6-1 6-1.Unfortunately for those watching at Roland Garros, a shoulder problem appeared to prevent Schwartzman from making the final set the shootout we were all hoping for.Djokovic heaped praise on the inspired Argentinian after his win.“I expected a difficult match with a lot of baseline rallies because the conditions are very heavy,” the 30-year-old said, via The Sun.“I’d like to congratulate him for a great battle because he played very, very well.”

Djokovic vs the umpire

Not only did Djokovic come up against an opponent playing above his world ranking suggests, but he also ran into an umpire who was willing to penalise him for taking too long between points.

In the fourth set, Djokovic, serving at 4-0 up, was docked a first serve after umpire Carlos Ramos deemed he was taking too much time.

Then, with Djokovic facing a break point, he received a warning from Ramos for unsportsmanlike conduct.

The umpire’s decision prompted a furious reaction from Djokovic, who immediately went to his chair.

“What did I say, why did you give me a warning?” Djokovic asks.

Ramos then tells Djokovic that it was his poor attitude that forced his decision.

“You’re losing your mind,” Djokovic retorts before walking away.

Watch: Djokovic gets into heated exchange with umpire

Watch the heated altercation below.

Djokovic is working with Agassi

Djokovic will have to up his game if he wants to win the tournament.

The world No.2 is playing in his first event with Andre Agassi as his coach and the American admitted he will work with Djokovic at Wimbledon if asked.

“If he wants me there I will come and figure it out,” Agassi, an eight-time Grand Slam winner, said, per The Sun.

“There’s a lot of responsibility so whatever’s practical and achievable, 100 per cent I will make the effort.”

Will Djokovic win the French Open? Let us know in the comments section below!