Tonda Eckert’s side blew the doors open within six minutes through Cyle Larin, before a Shea Charles wonder-strike made it two shortly after.
The U’s should have pulled one back through Tottenham Hotspur loanee Will Lankshear, who missed a glorious chance midway through the second half.
Saints have now gone 14 matches without defeat in all competitions, including a crucial run of 12 games with nine wins in the Championship.
Their play-off rivals also won their games, meaning Saints remain in sixth place, ahead of Wrexham on goal difference and three points behind Hull.
Saints seemed to take their foot off the gas for a period but this was still a comfortable win. Still in the play-off places heading into the break. #SaintsFC pic.twitter.com/ByuMXJb1cl
— George Rees-Julian (@rees_julian) March 21, 2026
Oxford, who remain 22nd in the table and are one point adrift of Portsmouth in safety, were looking to record a first-ever league double over Saints.
They beat Eckert’s 2-1 at Kassam Stadium on Boxing Day, but they had not visited Saints in a league fixture since a 3-0 defeat at the Dell in 1987.
Eckert made three changes to the starting XI that battled to a 1-0 win over Norwich on Wednesday, implementing a brand-new tactical system.
Charles, Tom Fellows and Cameron Archer came in, in a de facto 4-4-2 that saw Finn Azaz drift in with Fellows and Ryan Manning providing width.
And it was not just formation alterations that Eckert considered for the match, with Saints Foundation advertising boards placed around the pitch.
The idea was to limit Oxford’s long throw-ins, but they caused a ruckus after the visitors complained that they were too close to the playing area.
Saints staff were forced to frantically measure a two-meter distance with tape minutes before kick-off, to ensure they were in line with all regulations.
All protestations were valid, but felt a bit futile when Saints were two goals ahead inside 13 minutes, and the tie was effectively over as a contest.
Eckert’s instructions worked a dream as Taylor Harwood-Bellis found the high-and-wide Fellows for an easy cutback to Larin in the six-yard box.
It was the Canadian international’s third league strike since he signed on deadline day, and rounded out a week with a call-up to Jesse Marsch’s squad.
Charles was nominated for goal of the month in February and surely wrapped up the March prize with an audacious first-time hit from range.
Archer played back to the midfielder around 30 yards from the target after he received a short corner, and Charles sent it flying into the top corner.
Oxford remained two down at the break, but they did not roll over in the sunshine and more than threatened to peg Saints back after the restart.
Stanley Mills also saw two penalty appeals rightly waved away; one for a shoulder-to-shoulder with Flynn Downes and another for an Azaz handball.
Young striker Lankshear shot wide one-on-one with the big chance, having snatched possession from Harwood-Bellis for a free run at goal.
Fellows should have punished him with his first notch for Saints, but thrashed the crossbar from a tight angle after Ross Stewart’s parried shot.
Keeper Jamie Cumming made routine saves to deny Azaz from the edge of the area and a James Bree free-kick, as Saints coasted over the finishing line.
Having played 18 games already in 2026, they will enjoy a well-earned break in action until Arsenal visit in the FA Cup quarter-final in two weeks.
Saints: Peretz; Bree, Harwood-Bellis, Stephens, Manning (Quarshie, 90); Downes, Charles, Fellows (Matsuki, 76), Azaz (Oyekunle, 90); Archer (Edozie, 58), Larin (Stewart, 58).
Unused subs: Long, Wood, Jander, Bragg.
Booked: N/A.
Oxford: Cumming; Long, Brown, Konak (McDonnell, 69), Helik, Brannagan, Spencer, Mills (Emakhu, 87), Currie (Donley, 69), Peart-Harris (Jin-Woo, 76), Lankshear (Harris, 76).
Unused subs: Ingram, Vaulks, Prelec, Makosso.
Booked: Mills, Spencer, Helik.
Referee: Ben Toner.