OXFORD UTD 3 NEWCASTLE UTD 0
28. Matz Sels
27. Jesus Gamez
5. Grant Hanley
7. Achraf Lazaar
19. Massadio Haidara 77'
38. Curtis Good
14. Isaac Hayden
35. Daniel Barlaser
36. Yasin Ben El-Mhanni 68'
17. Ayoze Perez
45. Aleksandar Mitrovic
Subs
3. Paul Dummett
6. Jamaal Lascelles
11. Matt Ritchie 77'
12. Jonjo Shelvey
20. Yoan Gouffran 68'
21. Rob Elliot
22. DeAndre Yedlin
Oxford caused a major upset by thumping Sky Bet Championship high-flyers Newcastle 3-0 at the Kassam Stadium in the fourth round of the FA Cup.
Kane Hemmings put the Sky Bet League One outfit in front two minutes into the second half with his 13th goal of the season.
Aleksandar Mitrovic passed up the chance to equalise on 67 minutes when his penalty was saved by U's goalkeeper Simon Eastwood, before further home goals from Curtis Nelson and Toni Martinez sealed the shock result.
Newcastle boss Rafael Benitez made nine changes to the team which hammered Rotherham 4-0 last weekend, with only Isaac Hayden and Ayoze Perez keeping their places.
But it just was not Mitrovic's day. He lost his footing and fell over as he shaped to shoot in a good position after half an hour.
Eastwood then saved in quick succession from Jesus Gamez's half-volley and Yasin Ben El-Mhanni's drive.
Mitrovic should have scored when he charged through on goal, but Eastwood stuck out his foot to save.
And Eastwood saved again with his leg from Mitrovic just before half-time.
The opening goal arrived soon after the interval when Hemmings turned the ball in from four yards after Chey Dunkley headed Chris Maguire's cross back from the far post.
The Magpies had a great chance to level when Mitrovic was brought down in the box by Phil Edwards, but Eastwood brilliantly saved the Serbian's firmly-hit 67th-minute spot-kick down to his right.
Oxford centre-half Nelson made it 2-0 on 79 minutes, heading home Rob Hall's corner at the back post.
And 19-year-old Spanish striker Martinez added a third, on his debut, with a well-placed looping header three minutes from time.