And the Scottish Football Association compliance officer has issued a notice of complaint accusing Tonev of "excessive Misconduct by the use of offensive, insulting and abusive language of a racist nature".

Tonev, who made his Celtic debut against the Dons, has denied the allegations and he has until September 26 to respond, with a Hampden hearing pencilled in for October 9.

Manager Ronny Deila claimed on Thursday he had almost forgotten about the row following Tonev's denials.

''The journalists asked me earlier today and I couldn't remember what they were talking about,'' he said.

''I can't understand the problem, they are coming with something against us, that the player said didn't happen and I really believe him. That's it, finished.''

Meanwhile, Deila believes goalkeeper Craig Gordon is ready to resume his Scotland career in next month's European Championship qualifier against Georgia at Ibrox.

The 31-year-old has been a revelation at Parkhead since signing on a free in the summer after two years out of the game with injuries.

Gordon Strachan recalled the former Hearts and Sunderland player into his squad for the opening qualifier against Germany in Dortmund earlier in the month as back-up to Allan McGregor and David Marshall.

Another fine display by Gordon in Celtic's 2-2 Europa League Group D draw with Salzburg in Austria on Thursday night had Hoops boss Deila once more reaching for superlatives and Scotland fans relishing the prospect of three top-class keepers vying for the number one spot.

The Norwegian admitted he was "very glad" he did not have to choose between the three shot-stoppers but believes Gordon is ready to add to his 40 caps, the last of which was won against the Faroe Islands in a friendly at Pittodrie in 2010.

"Of course he can do that," said Deila on Friday. "I think Gordon is saying the same. He has keepers doing the same job and the question is who is doing it the best. That is his decision.

"I think Craig has been very good and, of course, Gordon has the problem with at least three goalkeepers I know about who are very good, so that is good for Scotland."

Speaking at the club's Lennoxtown training ground ahead of the Premiership clash with Motherwell at Parkhead on Sunday, Deila was confident his side will adapt back to the rigours of domestic football following their European sojourn.

Skipper Scott Brown returns to Glasgow today after being left behind in Austria due to a routine drugs test which led him to miss the flight home.

The former Stromsgodset boss said that Brown "will be ready for Sunday" as will the rest of the Hoops players.

He said: "It is about attitude and being ready for every game.

"That culture has been here for many years. The players are used to it.

"It is a very important game on Sunday and we will do everything we can to win it."

Meanwhile, Stefan Scepovic insists Celtic fans will see the best of him when he gets up to speed.

The Serbia international striker, 24, has made an inauspicious start to his Hoops career after signing from Sporting Gijon, being substituted in his first two matches against Aberdeen and Salzburg respectively.

"When I came here I was about 80 per cent fit and now I feel much better and I will get better week by week," he said.

"I need to work hard to become 100 per cent fit then everything will be okay.

"Even if you are one of the best players in the world, when you are not 100 per cent fit it is difficult."