Mikel Oyarzabal's penalty after a slightly harsh handball decision opened the scoring in the 29th minute and Real Sociedad had the game completely under control before goals from Mikel Merino and Portu in the 78th and 81st minutes assured the three points.
Despite being contained in the first quarter, Shanghai guard Peng Szu-Chin gradually paced the game by finishing baskets in consecutive fast breaks in a later period. Peng posted a game-high 22 points.
The defending champions, who had lost their first two games of the new season, have now bounced back with four consecutive wins to move up to second place.
Jiangsu were placed second in the group after the third round.
Sunday's rivals are Europa League champions Sevilla, and Koeman's big issue is in defense thanks to the red card shown to Clement Lenglet against Celta on Thursday.
Shanghai led by as many as 35 points in the final period.
Li felt a bit uncomfortable about Shandong's double team early in the match, but soon get used to that, making two baskets and feeding Chen's two layups, to help Inner Mongolia race ahead 19-15 in the first quarter.
Arsenal continued its positive start to the season with a 2-1 win at home over Sheffield United, but Mikel Arteta's side had to endure a frantic end to its game after David McGoldrick curled home a spectacular 83rd minute goal for the visitors.
Other leading clubs in Europe announced similar figures. Manchester United shipwrecked with an 80 million offer for Jadon Sancho as Borussia Dortmund demanded 120.
After Shaanxi narrowed the gap to five points, Wuhan pulled away as four players connected on 3-pointers in a row, and led 40-35 at halftime.
"I know footballers play under these conditions, but they are all the time moving," said Nadal after the latest ever finishing time for a match at the tournament.