Both sides limited the other to long-range efforts during a tame first half in their first meeting in more than 23 years.
Mark Harris saw a 12th-minute strike easily gathered by Viktor Johansson, while Stoke’s keeper palmed away a Tyler Goodrham strike from the edge of the box.
At the other end Eric Bocat had a 16th-minute strike blocked by Elliott Moore as Stoke went close from two successive stoppage-time corners.
Of more concern to both managers were midfield injuries sustained in the opening period as Stoke’s Lyndon Gooch limped off 12 minutes before the break while Oxford’s Cameron Brannagan also had to come off before the interval.
Brannagan’s replacement Rodrigues set up the opening goal as he cut in from the right after Goodrham had won the ball, and his pass found El Mizouni 12 yards out.
The goal lifted the confidence of the U’s as Dembele saw a deflected shot loop into Johansson’s arms soon after before Harris forced Stoke’s Swedish keeper to bat away a fierce effort from the edge of he box three minutes later.
Ben Wilmot did well to block a Rodrigues effort in the area after a pinpoint Peter Kioso pass after an hour as Stoke continued to be penned in.
Oxford had three great chances to score in the space of a minute as first Goodrham had a shot saved and from the resulting corner El Mizouni saw a powerful strike deflected over, before Kioso somehow contrived to miss with the goal gaping.
Andrew Moran’s effort soon after summed up Stoke’s day as he ballooned an effort high and wide from the edge of the box as Oxford goalkeeper Jamie Cumming had few saves to make.