Watch: Novak Djokovic practices with son Stefan in Belgrade 

Novak Djokovic appears to have gotten his season back on track after reaching the semifinals of the Serbia Open. The top seed defeated Laslo Djere in the second round and an in-form Miomir Kecmanovic in the quarterfinals, both in three sets.

The World No. 1 had a day off on Friday before his semifinal against Karen Khachanov, and made use of the time to practice with his son Stefan. Stefan, a self-professed Rafael Nadal fan, kept pace with his father with his array of groundstrokes, even managing to successfully lob the 20-time Grand Slam champion at one point.

The duo exchanged a fair few shots between them, watched on by the Serb's team and other fans at the Novak Tennis Center where the tournament is being held. A little while later, the 34-year-old stepped to the side and allowed other children of his son's age to use the court for practice.

Novak Djokovic takes on Karen Khachanov in the semifinals of the Serbia Open

Novak Djokovic takes on Karen Khachanov in the semifinals of the Serbia Open

Novak Djokovic will lock horns with third seed Karen Khachanov in the semifinals of the Serbia Open on Saturday. The Russian received a walkover in the round of 16 before disposing of qualifier Thiago Monteiro in the quarterfinals.

The World No. 1 has a 5-1 lead in the head-to-head against Khachanov, winning their last four encounters in straight sets. Their only previous encounter on clay, in the fourth round of the 2020 Roland Garros, was also won by the Serb and he will be the favorite to book his place in the final in Serbia.

The winner of the match will take on either sixth seed Fabio Fognini or second seed Andrey Rublev in the title clash. Djokovic is yet to lose against either player, leading the Italian 8-0 and Rublev 1-0 in the respective head-to-heads.

After his stint in Belgrade comes to a close, the Serb is scheduled to play at the Madrid Masters and the Rome Masters ahead of his title defense at Roland Garros.