Match ends, Newcastle United 0, Oxford United 0.
Newcastle manager Steve Bruce was hugely critical of his side and their "ridiculous" mistakes as they were held by Oxford United in the FA Cup fourth round at St James' Park.
The Magpies named a full-strength team, with debutant Nabil Bentaleb forcing a good save from Simon Eastwood from 20 yards.
Newcastle striker Joelinton had two goals correctly disallowed for offside.
League One side Oxford performed well and had the best chances to win the game in injury time, with Nathan Holland having a shot tipped over by Karl Darlow and Rob Dickie heading over the bar from the corner.
"I'm frustrated, disappointed, upset," said Bruce. "From the first minute to the last we were never good enough in possession.
"We gave the ball away. Our whole demeanour wasn't right. Oxford made it difficult for us. But we made it difficult for ourselves the way we surrendered possession. The amount of mistakes we made was ridiculous."
Newcastle at full strength but held again
Newcastle boss Bruce has a refreshing attitude to the FA Cup.
Having reached the 2014 final with Hull, he has targeted it as a tournament Newcastle can have a run in.
They have not reached the fifth round since 2005-06 and just as they did against Rochdale in the previous round, they will need a replay if they are to progress.
It was a celebratory atmosphere to start with - a 52,000 sell-out as rumours circulated about a possible Saudi Arabian takeover.
"The big crowd played their part today and we haven't done enough to make them enjoy it," said Bruce. "We huffed and puffed all day and didn't do enough."
Bruce named his strongest side - with Allan Saint-Maximin returning from injury and causing Oxford plenty of problems - as well as forcing Eastwood into three saves.
Joelinton had his usual struggles in front of goal but found the net twice, though both times while in offside positions.
They did have a strong penalty appeal on Joelinton in the first half, with captain Jamaal Lascelles heading over moments later.
Substitute Matty Longstaff went close moments after coming off the bench but in truth Newcastle did not do enough to win.
"We're still in the hat," said Bruce. "We'll be better when we go to Oxford. We couldn't be as poor as we were today."
Oxford fully deserve replay - and it could have been better
Oxford have been excellent this season, although performances have dipped recently - with one win in six games including this one.
They played well, although were not at their best, and may feel this is a game they would have won a month ago.
They let Newcastle know they were in for a battle early on when Dickie and Joelinton clashed in an aerial challenge and both players needed bandages on their heads for the majority of the game.
Watched by the largest crowd they have ever played in front of outside Wembley, they had their first ever VAR moment when the video assistant referee checked out a potential Magpies penalty for a tackle on Joelinton, but the U's escaped.
They contained Newcastle in the first half and created several match-winning chances in the second.
Marcus Browne will rue the moment he was sent in one-on-one by Alex Gorrin but shot straight at Darlow.
It could have been even better had Holland scored his first U's goal in injury time - or Dickie kept his header lower. But the Oxford owners will not complain about Newcastle heading to town for a replay in front of a full Kassam Stadium. And Robinson will fancy his chances of winning that.
'We didn't do enough' - what they said
Newcastle boss Steve Bruce speaking to BBC Match of the Day: "Frustrating, disappointing. We didn't do enough basically. Oxford, you have to say well done to them, they came and made it difficult for us but this is one of those where we didn't play well enough. We are still in the hat and we will go there and I am sure be better than we were tonight.
"We didn't pass the ball well enough, we didn't create enough. It was one of those afternoons where too many of them didn't get to a level they can. It is disappointment for all those thousands that came today and we didn't play well enough to get in the tie. It was a poor performance all round.
"It is what it is. We can't make many changes because of the injuries we have. We accept we have had a tough time with injuries so we will be as strong as we can be."
Oxford United manager Karl Robinson speaking to BBC Match of the Day: "It's incredible. We've played three Premier League teams this season and only one of them has beaten us - Manchester City. So I have got to give credit to my players.
"For the fans who turned out, it just shows you this cup has got a wonderful presence. My players were exceptional. Probably say we got the best chance of the game. All in all a very good performance by my players and I am very pleased with them.
"I thought we tried to play, which was brave of the players. We started nervously and I wasn't happy. I told them to relax and once they did that they got to grips with the game a bit more."
Both sides are in league action next Saturday. Oxford host Blackpool in League One (15:00 GMT), with Newcastle at home to Norwich in the Premier League (15:00).
- 6LascellesBooked at 11mins
- 36S LongstaffSubstituted forHaydenat 87'minutes
- 42BentalebSubstituted forAtsuat 80'minutes
- 10Saint-MaximinSubstituted forM Longstaffat 70'minutes
- 43M Longstaff
- 18SykesBooked at 85mins
- 6GorrinBooked at 75minsSubstituted forHansonat 90+1'minutes
- 16BaptisteBooked at 64mins
- 11Fosu-HenrySubstituted forAgyeiat 87'minutes
- 19MackieSubstituted forHollandat 77'minutes
- 13Stevens I
- Robert Jones
- Shots on Target
Second Half ends, Newcastle United 0, Oxford United 0.
Hand ball by Daniel Agyei (Oxford United).
Attempt missed. Robert Dickie (Oxford United) header from the centre of the box is too high following a corner.
Corner, Oxford United. Conceded by Karl Darlow.
Attempt saved. Nathan Holland (Oxford United) left footed shot from outside the box is saved in the bottom right corner.
Substitution, Oxford United. Jamie Hanson replaces Alex Rodriguez.
Attempt missed. Fabian Schär (Newcastle United) header from the centre of the box is too high following a corner.
Corner, Newcastle United. Conceded by Josh Ruffels.
Jamaal Lascelles (Newcastle United) wins a free kick in the attacking half.
Foul by Daniel Agyei (Oxford United).
Substitution, Newcastle United. Isaac Hayden replaces Sean Longstaff.
Substitution, Oxford United. Daniel Agyei replaces Tariqe Fosu-Henry.
Attempt missed. Joelinton (Newcastle United) left footed shot from the centre of the box is too high.
Corner, Newcastle United. Conceded by Elliott Moore.
Attempt blocked. Sean Longstaff (Newcastle United) right footed shot from outside the box is blocked.
Mark Sykes (Oxford United) is shown the yellow card for a bad foul.
Miguel Almirón (Newcastle United) wins a free kick in the attacking half.
Foul by Mark Sykes (Oxford United).
Corner, Oxford United. Conceded by DeAndre Yedlin.