"Jannik is in tremendous form, and he has been the best player for the last couple of years," said Djokovic.
The 21-year-old was the runner-up to Iga Swiatek in a one-sided showpiece match in 2022.
Swiatek bested the former world number three 6-1, 7-5 in just over 90 minutes on Court Philippe Chatrier to continue her bid to equal a 102-year record by winning four successive French Open titles.
Sabalenka suffered her first loss to Zheng in seven career meetings in the Rome quarter-finals last month and she went behind early in the opening set at a half-full Court Philippe Chatrier.
Reigning champion Carlos Alcaraz won a war of attrition with American 13th seed Ben Shelton to reach the French Open quarter-finals on Sunday.
Football fan Djokovic may have missed the majority of PSG's 5-0 demolition of Inter, but the Serb told reporters after his win the final made its presence felt on court in Paris.
Top seed Jannik Sinner dismissed world number 34 Jiri Lehecka in straight sets on Saturday at Roland Garros as the Italian booked his place in the fourth round.
"When I was walking on court a little girl put a drawing on my bench, I kept it. It's my lucky charm," she said.
Four-time Grand Slam champion Alcaraz arrived as the favourite at Roland Garros after securing the Monte Carlo Masters and Italian Open trophies in the build-up to the clay-court major.
"Jannik is in tremendous form, and he has been the best player for the last couple of years," said Djokovic.
The 21-year-old was the runner-up to Iga Swiatek in a one-sided showpiece match in 2022.
Swiatek bested the former world number three 6-1, 7-5 in just over 90 minutes on Court Philippe Chatrier to continue her bid to equal a 102-year record by winning four successive French Open titles.
Sabalenka suffered her first loss to Zheng in seven career meetings in the Rome quarter-finals last month and she went behind early in the opening set at a half-full Court Philippe Chatrier.
Reigning champion Carlos Alcaraz won a war of attrition with American 13th seed Ben Shelton to reach the French Open quarter-finals on Sunday.
Football fan Djokovic may have missed the majority of PSG's 5-0 demolition of Inter, but the Serb told reporters after his win the final made its presence felt on court in Paris.
Top seed Jannik Sinner dismissed world number 34 Jiri Lehecka in straight sets on Saturday at Roland Garros as the Italian booked his place in the fourth round.
"When I was walking on court a little girl put a drawing on my bench, I kept it. It's my lucky charm," she said.
Four-time Grand Slam champion Alcaraz arrived as the favourite at Roland Garros after securing the Monte Carlo Masters and Italian Open trophies in the build-up to the clay-court major.
On Sunday, we witnessed the farewell of a tennis legend: Rafael Nadal, “King of Clay” and a symbol of inspiration.