Watch: Novak Djokovic trains at Tipsarevic Tennis Academy in Belgrade 

World No. 2 Novak Djokovic is currently in Belgrade, Serbia, and was spotted training at the Tipsarevic Tennis Academy on Saturday. The 20-time Grand Slam winner was seen practicing some forehand and backhand drills.

Djokovic suffered a shock defeat at the hands of Czech qualifier Jiri Vesely in the quarterfinals of the Dubai Tennis Championships last week. Vesely defeated the Serb in straight sets, knocking him out of the tournament and ending his stay at No. 1

After the defeat in Dubai, Djokovic returned to Belgrade, where he along with former World No. 8 Janko Tipsarevic.

Tipsarevic, a former Serbian player, posted a picture with Djokovic and other players from his academy on his Instagram handle. He said that a "special guest" recently visited his academy, referring to the World No. 2. He also used a goat emoji while referring to Djokovic, hailing him as the greatest player of all time. The two were joined by former World No. 12 Viktor Troicki.

"Got a special 🐐 guest, helping us out today," Tipsarevic captioned the post.

Djokovic enjoyed a 5-2 lead in the head-to-head over Tipsarevic, having defeated him on all three surfaces on the ATP tour.

Janko Tipsarevic with Novak Djokovic at the Miami Open

Novak Djokovic will not compete at Sunshine Double in 2022

Novak Djokovic at the Tokyo Olympics 2020

Despite undertaking a training session in Belgrade, Djokovic is unlikely to take part in any tournament in March. The Serb is on the entry list for the Indian Wells Masters and Miami Masters, collectively known as the Sunshine Double, but hinted that he won't travel to the United States as he is unvaccinated.

Interestingly, the 34-year-old is the only tennis player to have won the Sunshine Double four times.

The Serb was recently given the green light to defend his title at the 2022 French Open and contest in Monte-Carlo after the French government eased up on its vaccination policy. The country will remove vaccine passes in a couple of weeks, paving the way for the Serb to compete without being vaccinated. However, the situation could change with evolving COVID variants and rules set by countries.

Djokovic is also expected to play at the Italian Open, a Masters event that he has won on five occasions.