A handful of Oxford United fans brought shame on their club in ugly scenes involving match stewards.

Police are now studying video evidence after crowd trouble marred Jim Smith's first away game as the U's manager at Mansfield on Saturday.

Oxford fans caused a five-minute hold-up to play near the end of the club's 1-0 defeat at the Field Mill Ground.

At least two U's supporters ran onto the perimeter of the pitch towards Mansfield supporters who had been goading them, and were rugby-tackled by stewards.

Several dozen other Oxford fans were then involved in confrontations with stewards.

Some visiting fans claimed that the trouble started when a bottle was thrown into the away end, injuring one person.

And others were unhappy that Mansfield stewards were treating them as hooligans, but doing nothing about home fans who were behaving exactly the same.

Nevertheless, they were shameful scenes, which brought condemnation from both Jim Smith and new Oxford United chairman Nick Merry.

Mr Smith said: "We can't defend that. Apparently somebody threw a bottle into our boys and it smashed on the floor, or whatever.

"We want them to support us and we want to have tremendous support away from home, but we don't want to be associated with fans jumping over the fence and fighting with stewards and so forth. We've got to be bigger than that.

"I understand the frustrations but we have all got to be bigger than that."

Mr Merry wanted to learn the full facts before making a statement, but said: "Obviously, I'm not very happy about it, at all."

The Mansfield Town ground controller said he would not comment until officers had been able to view all the CCTV evidence of the trouble.

Police have also asked photographers at the match to send them any pictures they took of the disturbances The trouble began moments after Mansfield were controversially awarded an 84th-minute goal, which ultimately decided the game.

United goalkeeper Andrea Guatelli tried to claw out Danny Reet's header at the far post.

The Italian was inside his goal as he made the save, but insisted he had kept the ball out.

Yet assistant referee James Cox flagged that it had crossed the line.

The linesman was under intense pressure from home fans after earlier disallowing a goal, which was a very tight decision, and then making a bad blunder in a subsequent offside decision.

Mansfield manager Peter Shirtliff said: "I don't know if it was a goal, but I thought the one we had disallowed was a goal.

"It did look as if the keeper dived back into his net to pull it out, but it is difficult to see from my angle.

"I was very disappointed with what happened after the goal, fans running onto the pitch and having to be rugby-tackled by stewards.

"I haven't seen that for a long time and it's not very pleasant."

No one from Nottinghamshire Police was available for comment yesterday.

Thames Valley Police spokesman James Clements told the Oxford Mail: "The force's football liaison officers will be linking up with officers in Mansfield."