Sir Alex Ferguson bemoaned the failure of the referee Chris Foy to give his Manchester United side a penalty in their 1-0 defeat to Arsenal at the Emirates Stadium on Sunday.

Although Ferguson admitted Arsenal had a good claim for a penalty when Nemanja Vidic handled in the first half, the manager felt hard done by as the referee ignored the Arsenal defender Gaël Clichy's clip on Michael Owen's calf.

"It's too big a game not to get the decisions right," Ferguson told Sky Sports News. "It balances out in that respect but I think it was difficult to see that one [Vidic's handball] but the one at the end, [Gaël] Clichy knew, he put his hands up in horror."

Ferguson added: "Obviously it gives Chelsea a major chance now and that's what happens when you get these decisions. They got one at Old Trafford last season so that's the worry now. But in terms of ability – a game at Old Trafford, the supporters will be ready for it – and so will our players."

Owen said on Twitter of the incident: "Not seen tv replay but don't need to as I know mine was a pen. Heard people saying Arsenal should of had one too so can't complain too much." Wayne Rooney added on Twitter: "Bad result. But still in our hands. We have to move on to Wednesday now."

Ferguson admitted that his team had disappointed until Arsenal scored through Aaron Ramsey in the 56th minute. "After that we dominated and I think we deserved something," he said. "I think we didn't use the ball properly but once we lost the goal we were in their half most of the time."

Robin van Persie said his side "wanted it more" after Arsenal blew the Premier League title race wide open with their victory. Ramsey's goal – his first since January 2010 – saw United remain three points clear of Chelsea, whom they face next week at Old Trafford.

Van Persie said of the Vidic incident: "A clear penalty and in my opinion a straight red." Asked what the referee had said to him, he replied: "At first nothing because he wasn't sure, but I asked him again just after half-time and he said it wasn't a penalty but I'm sure if he sees it again then he will agree with me.

"If that [United's penalty appeal wrongly turned down] is the case then it's 1-1 on that one but in the end I think we played better today. We wanted it more. They played just on the counterattack so in the end I think [it was] a fair result. It was all about pride today. The fans were great. It was up to us to show some dignity and some honour. We did that today so we're very pleased with that."

The match-winner Ramsey – who was only in the team because of a thigh injury to the captain Cesc Fábregas – urged Arsenal to press on and finish the season on a high. "Our target was just to keep going now until the end of the season, to win all our games and see where we end up from there," he said. "We've done the first bit today. We've still got a few more games left so hopefully we can win them as well."