Reds will have to overturn a three-goal deficit away from home to make the semi-finals
The Spanish giants prevailed 4-3 on penalties after a 1-1 draw on the night meant the tie ended 4-4 on aggregate.
Gloucester City's time in National League North comes to an end on Saturday with a home game against Scunthorpe United - and manager Mike Cook cannot wait for the season to be over. The Tigers were beaten 4-1 at Curzon Ashton last weekend, going in