City matched their opponents, who play in the league above, for much of the match until tiredness kicked in which made the score more flattering for the visitors.
Lauren May showed signs of continuing from where she left off last season by getting herself on the scoresheet again after scoring 33 goals across last campaign.
It was a cagey opening to the match with both sides feeling each other out in the early stages. Stevenage then had two great chances to break the deadlock; first came an excellent save from Nat Morris who pushed an effort just wide of the post. They then had an even better chance after their striker was well found at the far post but shot over from close range.
The pressure eventually paid for the visitors who scored a brilliant free-kick from 20-yards out which found the top corner of the City net.
Waheed Ramzan's side responded well as Lauren May was put through to the right of the goal but saw her shot straight at the keeper.
Tizzy Russell-Cartwright was having lots of joy down the right-hand side and her runs created chances for both May and Ellie White but neither could trouble the goalkeeper.
City's best chance came after 35 minutes courtesy of Russell-Cartwright who was put through 1-on-1 with the keeper but her shot was well saved.
The Hoops finally got the goal they deserved five minutes before the break thanks to an excellent ball from deep played in May who also found herself 1-on-1 but this time the ball found the back of the net by cleverly dinking the ball over the onrushing goalkeeper.
Stevenage then restored their lead five minutes after half-time due to a hopeful shot from the edge of the box being tipped onto the bar by Morris before it rebounded to their number 10 who slotted into an empty net.
The next 20 minutes then saw both sides trade attempts on goal with Ella Dawkins, Danielle Anderson and Edie Stilwell-Garrett all trying their luck from distance but failing to beat the goalkeeper.
As the game went into the closing stages, Stevenage's fitness advantage was showing and eventually scored two goals in four minutes to seal the win.
The third was a smart finish from the angle which found the bottom corner and the fourth was through a chipped finish from the left side of the box which just evaded the fingertips of Nat Morris.
Overall, Oxford City can take lots of heart from this performance going into the new season which starts at home to Newbury on September the 8th.