The 28-year-old was earlier forced to leave a training session at Brazil's Granja Comary base in Teresopolis, near Rio de Janeiro, to undergo physiotherapy.
Facing a perfect Nadal, Djokovic was unable to hold any of his three service games in the first set, and finally secured his first service of the match in the opening game of the second set, after saving three break points. But the Spaniard quickly broke twice in the third and fifth game to storm to a 4-1 lead.
Meanwhile, football training is to start in mid-October to prepare teams for the start of Malawi's top league in November.
Vasco dropped to 10th in the standings, having lost four of their past five fixtures.
Zhejiang coach Gu Jiaqing admitted his side were not strong enough defensively against Henan's key players.
"I could not just rest on the plane as my players did, but distributed some time to analyze opponents' tactics. I was so tired then," Ji recalled.
Ji was dubbed "Female Kobe" for her shooting posture and scoring ability similar to deceased American legend Kobe Bryant, who was killed in a helicopter crash in January.
"I don't have much to say but that I was completely overplayed by Rafa, by a better player on the court," said Djokovic in the post-match conference.
Xinjiang's Han Xu finished with a team-high 19 points. Liu Tongyi and Wang Lili each had 17.
"We came into this match with the mentality of challenging Xinjiang. I hoped that our players could show our style in such an intense game," said Jiangsu coach Ding Tie.
The two players exchanged serves in the first two of the second set, but after Kenin called for a medical timeout at 2-1 down, the battle was in Swiatek's dominance as she swept four consecutive games to wrap up the second set in just 31 minutes.