The full-back scored in the 89th minute to punish United, who had spurned a number of glorious opportunities in the first half.
Raoul Petretta found space to cross down the left and his low ball was perfect for Lang to tap home at the far post to give Basel a shock victory.
Daley Blind will be disappointed with how he let Lang get the wrong side of him and Jose Mourinho no doubt more so.
The win moves Basel level on points with CSKA in second in Group A.
Check out the goal for yourself below:
Check out this awesome video: Michael Lang Goal ~ Basel vs Manchester United 1-0 22/11/2017 Champions League https://t.co/9s7ZTAVFCx
— jamal (@jamalcosto9) 22 November 2017