Dundee United boss Craig Levein refused to criticise referee Charlie Richmond over the penalty appeal he waved away against Celtic on Sunday.Shortly after Paul Hartley had given the visitors the lead on 51 minutes with a deflected shot from inside the box, Richmond waved play on when United striker Roy O'Donovan appeared to be tripped by defender Gary Caldwell inside the box.

Richmond then injured himself running into Celtic midfielder Shunsuke Nakamura and had to be replaced by fourth official Iain Brines - before Francisco Sandaza, on as a second-half substitute for Warren Feeney, nipped in at the near post to flick a Craig Conway cross past Hoops goalkeeper Artur Boruc and secure a draw in the SPL match.

Levein was fined a record £5,000 last week for castigating referee Mike McCurry for a catalogue of errors during a 3-1 defeat at Rangers in May.

Alluding to that game, the United boss went easy on Richmond - who had been taken to hospital.

He said: "I haven't seen it, but everybody tells me it was a stonewall penalty.

"I thought he was looking right at it.

"But I don't know. I like Charlie and I think he's a decent referee.

"At least it was only one mistake inside the penalty box today, and I've got to put that down as an error - because the alternative isn't worth thinking about.

"If I can't speak my mind and represent my football club and come out after a game where we've had five blatant decisions go against us, then I shouldn't be doing my job.

"I will continue to speak out when I feel we've been treated in an unfair manner."

Celtic manager Gordon Strachan, who refused to dismiss rumours of a return to Parkhead for Aston Villa striker Shaun Maloney but silenced speculation that Mikael Silvestre would arrive from Manchester United on a loan deal, had a different view of the penalty incident.

He said: "I didn't think it was a penalty - because I was convinced he was going to give a free-kick before it for number 10 (O'Donovan), not for the first time, not even looking at the ball and jumping in to 'Mick' [Stephen McManus].

"I'm sure the referees with their extra £300 or £400 (wage rise) have extra time to buy a video and study that."

Strachan insists his side paid for profligacy in front of goal, especially in the case of last season's top scorer Scott McDonald - who missed a late sitter.

He said: "We played better than last week (against St Mirren) and looked livelier.

"We had the opportunity to finish the game and couldn't take it, so we have nobody to blame apart from ourselves.

"But the players can be pleased with some good performances at times. It could be a big point, come the end of the season."

O'Donovan tried not to put too much emphasis on the penalty incident, saying: "It could have been a penalty - and I thought it was a penalty. But then again, I'm biased.

"He didn't give it; we can't argue too much, and a draw was a fair result.

"Had we got the penalty and scored, we could have pressed on. But a point is better than nothing."

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