Djokovic survives Bu scare to go 31-0 in Beijing, matching Nadal

A set down, a medical timeout, and still unbeaten

Novak Djokovic has never lost a match at the China Open, and on Friday he refused to let that change. The sixth seed came from a set down to beat Chinese wild card Bu Yunchaokete 4-6, 7-6(2), 6-2 in nearly three hours and move into the quarterfinals at Beijing.

It was anything but routine. Bu, roared on by a packed home crowd, took the opening set, and Djokovic then let a break advantage slip in the second. Midway through that set the Serbian needed on-court treatment for what appeared to be a problem around his rib area, the same region that had been treated during a medical timeout in his opening match on Wednesday, according to the Associated Press.

Whatever was bothering him, it did not show in the decisive moments. Djokovic dominated the tiebreak 7-2, then broke Bu twice to race to a 4-0 lead in the third set. Tennis Majors noted that after the tiebreak his forehand gained consistency and depth and he started winning far more of the points in which he had the chance to attack.

"The atmosphere was amazing. Packed stadium again for three hours — what a match to be a part of," Djokovic said afterwards.

31-0: level with Nadal's Paris start

The win lifted Djokovic's record in Beijing to 31-0. That equals Rafael Nadal's unbeaten start at Roland Garros, where the Spaniard won his first 31 matches before his famous 2009 defeat to Robin Söderling, and it ties the best opening run at a single tournament by any man in the Open Era.

Djokovic has won the China Open six times, a record, although his most recent title came back in 2015. Friday's victory also brought a string of other milestones, according to Tennis Majors: it was his seventh quarterfinal in Beijing, another record at the event, and the 228th tour-level quarterfinal of his career. At 39, he became the oldest quarterfinalist at an ATP 500 event since 2009, surpassing a mark previously held by Roger Federer.

His campaign had started with a 6-3, 7-6(2) win over Nuno Borges, a match that also featured the first medical timeout of the week. How his body responds over the next 48 hours will be the key question in the Djokovic camp.

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Zverev looms in the last eight

The extra rest could prove valuable. Djokovic will face either top seed Alexander Zverev or home wild card Shang Juncheng in Sunday's quarterfinal, with the winner of their Saturday clash having roughly 24 hours less to recover than the Serbian. Shang reached the second round with a 5-7, 6-3, 7-5 win over Sebastián Báez, while Zverev beat Cameron Norrie 7-6(1), 6-4 on Thursday.

Elsewhere, Hubert Hurkacz needed three sets to see off French qualifier Arthur Gea 7-6(5), 6-7(5), 6-2, and Karen Khachanov beat Slovak qualifier Alex Molčan 7-5, 6-3, according to the ATP's official results. Third seed Daniil Medvedev opened his tournament with a 6-4, 6-2 win over qualifier Pablo Carreño Busta.

For Djokovic, the target is clear: three more wins would give him a seventh Beijing crown, eleven years after his last, and keep a perfect record intact that only one other man in the Open Era has matched at a single event.