Novak Djokovic survives another fitness scare to reach China Open quarter-finals

The 39-year-old Serbian battled to a 4-6, 7-6(7-2), 6-2 victory over the world No 104 on Friday, extending his record at the tournament to 31 wins from 31 matches.

However, Djokovic's latest victory was again overshadowed by concerns over his fitness.

After surrendering a break in the second set, the sixth seed required a medical timeout for what appeared to be a problem around his torso or rib area. He had received treatment in a similar area during his opening-round win over Nuno Borges earlier in the week.

Bu had made life uncomfortable for Djokovic throughout the contest, using his serve and aggressive baseline play to keep the Serbian under pressure. The Chinese wildcard took the opening set and looked capable of producing another major upset in Beijing.

Djokovic, though, responded when it mattered most. He dominated the second-set tiebreak to level the match before finding another gear in the decider.

The former world No 1 immediately put Bu under pressure, winning four games in succession to move 4-0 ahead before completing the comeback in two hours and 52 minutes.

"Amazing atmosphere tonight," Djokovic told the crowd afterwards. "I tried to give my all."

He also acknowledged the difficulty of dealing with Bu's game, saying he had to serve well at important moments because his opponent was "so solid" and difficult to break down.

The victory continues Djokovic's remarkable record in Beijing, where he has won the title six times, although his last triumph came in 2015.

More importantly, it provides another opportunity for the Serbian to build momentum after a difficult year in which ongoing health problems have repeatedly disrupted his progress.

Djokovic previously revealed he had been dealing with an ongoing health condition and, after his first-round victory, admitted he had struggled to remain fresh during the match.

His fitness problems were particularly evident at the US Open, where he suffered a shock first-round defeat after experiencing vomiting and cramping on court.

Yet Djokovic struck a more positive note in Beijing after his latest victory, suggesting he was finally able to focus more fully on tennis.

"Finally that I get to play tennis, you know, without really thinking about all the other things happening," he said.

The support he has received from the Beijing crowd has also remained a feature of his campaign, with Djokovic once again receiving a strong reception despite facing a Chinese opponent.

He will now face either top seed Alexander Zverev or China's Juncheng Shang in the quarter-finals.

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