Former international Chen Xiaojia powered Jiangsu's offense through consecutive baskets as Jiangsu went up 23-18 at the end of the first quarter.
But former Changchun Yatai striker Marinho equalized on the stroke of half-time and Kaio Jorge then bundled home from close range to guarantee Santos their fourth win from five matches.
Koeman also discussed rumors over interest from other clubs in winger Ousmane Dembele, whose sale would raise funds for new arrivals.
The other two German participants - RB Leipzig and Borussia Monchengladbach - have harder tasks in Groups F and B respectively.
Ghana's most recent matches were wins against South Africa and Sao Tome and Principe in November 2019. Enditem
Also on Monday, Hebei China Fortune beat Qingdao Huanghai 3-1, so Hebei will face Guangzhou Evergrande in the next stage.
A winless run of 18 games from the end of last season seems to endanger the club's future more than ever before if the right steps aren't made now.
Another game on Monday saw Tianjin take a 3-0 (25-17, 25-17, 25-17) victory over Fujian.
"To make things easier I told the players yesterday [Wednesday] that this was the right way to go," he added, suggesting the decision was of his own volition.
Instead, the federation will launch a virtual race, to be announced within the next days.
Local favourite Kristina Mladenovic was a victim of a missed call in her first round defeat to Laura Siegemund of Germany on Tuesday.