Peterborough leapfrogged Oxford in the League One play-off race after thumping their fellow promotion contenders 3-0.
Posh’s first-half dominance was rewarded with two goals from Hector Kyprianou and Ricky-Jade Jones, with substitute Ryan De Havilland adding a third late on.
Kyprianou had the simple task of breaking the deadlock in the 24th minute after Harrison Burrows cut the ball back into his path following an Archie Collins blast being parried by goalkeeper James Beadle.
The advantage doubled 10 minutes later when Jones sped onto a fine Ephron Mason-Clark pass, skipped round Beadle and finished into a gaping net.
Fine Beadle stops from Joel Randall and Jones then followed as Darren Ferguson’s men dominated the opening 45 minutes.
Oxford were livelier in the second period as Billy Bodin demanded a penalty for a shove after firing a Josh Murphy cross wide just after the hour but only received a caution from referee James Linington for his appeal.
Marcus McGuane then tested Posh keeper Nicholas Bilokapic from long range before the home side went back on the attack with Beadle denying Kwame Poku and Mason-Clark.
But the hosts struck again in the second minute of stoppage time when substitute David Ajiboye picked out fellow replacement De Havilland to finish.