BEIJING -- Novak Djokovic rallied to beat Bu Yunchaokete and maintain his flawless record at the China Open despite again needing a medical timeout on Friday.
The sixth-ranked Djokovic won 4-6, 7-6 (2), 6-2 to reach the quarterfinals and extend his record to 31-0 at the Beijing tournament, which he has won six times, the last in 2015.
"I had to play very well. I had to serve well in the right moments," Djokovic said. "He was so solid. I struggled to really find holes in his game and was hitting his spots really well with his serve.
"Credit to him for playing well. The atmosphere was amazing. Packed stadium again for three hours -- what a match to be a part of."
Novak Djokovic rallied for a 4-6, 7-6 (2), 6-2 victory over Bu Yunchaokete to improve to 31-0 all-time at the China Open. Fred Lee/Getty Images Djokovic squandered a break advantage in the second set and also needed treatment on court. It appeared to be a problem around his rib area, similar to where he had been treated during a medical timeout during his first-round match on Wednesday.
Djokovic showed little ill effects afterwards, dominating the tiebreaker and then breaking Bu's serve twice to storm into a 4-0 lead in the third set.
The 39-year-old Djokovic sealed the win on the second of three match points with a crosscourt backhand.
He will play either top-seeded Alexander Zverev or China's Juncheng Shang in the quarterfinals.
In a first-round match, sixth-seeded Daniil Medvedev eased past Pablo Carreno Busta 6-4, 6-2 and will next face Jan-Lennard Struff.
In the women's tournament, second-seeded Aryna Sabalenka took just 62 minutes to defeat Renata Zarazua 6-1, 6-3. It was Sabalenka's first match since losing the US Open final to Elena Rybakina.
In contrast, it took Naomi Osaka exactly double that time to see off Maria Timofeeva, with the No. 12 seed eventually prevailing 6-3, 3-6, 6-3.