Bayern grew into the game as the clock ticked, and Muller's goal was reversed by the video assistant referee before Lewandowski nodded home Serge Gnabry's cross to mark his 100th goal on home soil.
Earlier on Friday, Jiangsu defeated Shanghai 3-0 (25-17, 25-20, 26-24) in the third-place match.
"We executed the tactics and contained them quite well," Wang Siyu noted.
Han Xu got 13 points and 10 rebounds for Xinjiang who had another four players scoring in the double-digits. Enditem
Clubs like Bayern had to accept a substantial loss in quality after the departures of Thiago Alcantara (Liverpool), Philippe Coutinho (back to Barcelona), and Ivan Perisic (Inter).
Jose Bordalas' men now travel to play Real Sociedad - one of the most attractive sides in La Liga, but who have struggled for form at home since the return of football in June.
"We inflicted great pressure on our opponents throughout the game. Offensively we played inside out and showed our level," Inner Mongolia coach Zheng Wei reflected.
Another 10-0 surge into the second quarter extended Beijing's advantage to over 25 points. Daqing's loose defense provided Beijing many easy baskets in the paint, and the latter also found their range, going into the break with a 57-28 lead.
The emerging powerhouse tamed Hebei by a 44-point gap on Friday. Center Li Yueru shot 10 of 12 from the field to finish with a game-high 21 points. Chen Liyu helped with 16. Wei Wei nailed 14 points off the bench.
Colombia will face Venezuela in Barranquilla on Friday and Chile in Santiago four days later.
In addition, the quality of the 10 member teams means there are no easy games for anyone; the region boasts four national sides in FIFA's current top 10 and seven in the top 25.