The Serbian was trying to come back in the third set, converting his first breakpoint after losing the previous four in the sixth game. But a deadly double-fault in the 11th gave Nadal a chance to serve for the title.
Xinjiang's Han Xu finished with a team-high 19 points. Liu Tongyi and Wang Lili each had 17.
"We improved our ball movement with the match going deep. Players had expected to win this match through an easy route. After halftime adjustment, we had a different look in the second half," said Zhejiang coach Gu Jiaqing.
It also mandated face coverings to be worn at all times except when eating or drinking, and strongly discouraged singing, chanting and shouting at outdoor gatherings due to a higher risk of COVID-19 transmission.
Shandong trimmed the deficit to four points midway through the last quarter, but could not get closer afterwards.
"We always talk to each other and I know him from our time in the Barcelona youth system, we talk about the time we spent there," said Adama.
Garcia has so far failed to sign a new contract with Manchester City and with his current deal due to expire next June, the club must now decide whether to try and cash in on him in January or to see him move for free at the end of the season.
"As a young team, we haven't played many tough games like this one, so we really cherish this win," Sun noted.
"We tightened up defense on their three-pointers from the second quarter, also improving our offense down the stretch," Henan coach Li Jianxin reflected.
The Swiss need a positive result from their visit to Madrid after losing to Ukraine and being held at home by Germany, but with players such as Granit Xhaka in their side they are likely to provide another stiff test for Spain. Enditem
The fifth-ranked team will advance to an inter-continental playoff over two legs. Enditem