Oxford boss Chris Wilder admitted two of his players had a dressing-room row after their 2-0 win over Northampton.
Peter Leven was angry that Tom Craddock insisted on taking a late spot-kick despite the fact Leven is the club's designated penalty taker.
Craddock, who had opened the scoring for the Us after 50 minutes, had won the 85th-minute penalty, when he was brought down by John Johnson. He insisted on holding onto the ball, rather than hand it to Leven, and taking the penalty, but then blazed it over the bar.
The row proved immaterial when substitute Deane Smalley sealed the points with a second Oxford goal two minutes later, and Wilder said afterwards: "The two players have had a row in there.
"I'm on Leven's side to be perfectly honest. He takes them and scored with his last one. They should have sorted it out before the game. But the row shows they care. Both players are passionate. I had my say on it but I let them get on with it, and now it's done and dusted as far as I'm concerned."
In the end, both teams missed late spot-kicks because Northampton striker Adebayo Akinfenwa was also given the opportunity from 12 yards in stoppage time when Damian Batt handled Lewis Young's shot. But Akinfenwa also missed, with Oxford keeper Ryan Clarke pulling off a brilliant low save to his left.
Northampton's defeat stretched their winless run to 11 games, but new manager Aidy Boothroyd saw some encouraging signs, saying: "I thought there was a bit of positive. We played well in the first half and created some good chances.
"But in the second half we made silly mistakes, and if you make silly mistakes, whatever level it is, you get punished. There's a really fine line between winning and losing.
"Our season is in three parts as I see it. From now until January we need to get results, we need to get players in during January, and then we'll see what we can do between January and the end of the season.
"But I knew it would be a challenge when I took the job. All the players are on trial, whether they're players who have played two games or 200 games. I need to see what they're like, because we're looking to build something here."