Third Division Oxford gained a famous win as they moved into the second round of the Worthington Cup.
James Hunt scored for them early in the first half and in the second they resisted everything City could throw at them. They finished with just ten men after striker Andy Scott was sent off four minutes from time for a second booking while manager Ian Atkins was also sent into the stand for arguing over that decision.
Atkins had been determined his side would go into the tie as the underdogs when he described City's home form as awesome.
But his briefing to his third division players was to challenge hard and break up Bristol's attack.
The plan worked perfectly as Hunt came in from the left byline to score the first goal City had let in at home this season.
He swept past Joe Burnell and his low shot left keeper Steve Phillips stranded as it took a deflection off Matt Hill.
City were comfortable on the ball but their finishing was simply not there and a growing sense of frustration saw them pulled up for ten fouls in the first half.
Oxford's tenacious midfielder Dave Savage gave his side a distinct edge as they rode out the loss of his partner Matt Robinson injured midway through the first half.
City's approach work was a shade too casual but this mood was shaken out of them by manager Danny Wilson at the break.
The second half was almost all one-way traffic and as Oxford desperately pulled players back behind the ball, there were bookings for Savage and Scott McNiven.
The chance of an equaliser came and went as Lee Peacock mistimed his lunge at a Scott Murray cross but City kept their patience as they built attack after attack.
It was Murray again who so nearly saved the game for them but Lee Matthews, who had come on as a substitute for Christian Roberts after 67 minutes incredibly missed from two yards lifting Murray's cross high over the bar