The Red Devils managed to hold on to a 1-1 draw at the Bernabeu in the first leg of the round-of-16 tie.
"The lads are disappointed in the changing room," Goal.com quotes Jones as saying. "We could have scored more goals and on another day we would have done that. A bit more luck and it might have gone in. We've got to repeat the same sort of performance at Old Trafford."
The return leg is scheduled for March 5.