Robert Hall and James Constable scored two apiece as Oxford beat Plymouth Argyle with an impressive performance.
The U's led when Hall lashed home from 12 yards after Argyle keeper Jake Cole had parried Alfie Potter's header.
Simon Walton levelled with a penalty after Michael Duberry had fouled Jared Sims but Hall volleyed home for 2-1.
Constable netted from 18 yards and Peter Leven chipped Cole brilliantly from the edge of the box before Constable scored again when one-on-one.
Hall, 18, has now scored six goals in nine games during his loan spell from West Ham.
The result lifts Oxford up to fifth and leaves Plymouth bottom, five points off safety.
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Oxford United boss Chris Wilder told BBC Oxford:
"It wasn't an easy game for us. Full credit to Plymouth - they suffered a few injuries but had a right go at it.
"They caused us a few problems but we got ourselves in front.
"We have a bit of a habit of taking the foot of the gas and letting teams back into it. The difference was that tonight we got a couple of goals in quick succession and ran out comfortable winners."