The Parkhead side lead Rangers at the top of the Clydesdale Bank Premier League by three points but they crashed out of the quarter-finals of the Homecoming Scottish Cup against St Mirren on Saturday which led to more criticism of Vennegoor of Hesselink and Samaras, who have failed to score in the last 25 games between them.

McDonald, however, with 15 goals to his name this season, is looking for a return to form in Sunday's Co-operative Insurance Cup final against Rangers at Hampden.

"I put myself under pressure, week in, week out, anyway," he told Scottish Television.

"And if I'm not scoring goals then I'm not a happy man, that's just the way I am.

"My two other partners are fully confident guys, they believe in their own ability and so do we around them.

"It seems like one week to the next that we go from such a high down to rock bottom and so there is no difference this week but we will pick ourselves up and look forward to the final."

McDonald believes the outcome of Sunday's game will have no bearing on the title race.

He said: "I can't see that happening.

"People have all their psychological theories - if you win it then the other team is down in the dumps - but it can work the other way as well.

"The team that loses it will have their pride hurt and would want to get back and win the title.

"People can say what they like but it's all down to performances and both teams will have their blips."

Rangers midfielder Lee McCulloch mostly concurred with his Parkhead rival saying:

"It doesn't mean to say that if you win the final you will automatically win the league.

"It will be a big psychological boost but it is a one-off game and anything can happen."

Rangers striker Nacho Novo, who has been sidelined since damaging his ankle against Dundee United at the end of January, revealed he is on the way back to full fitness and is hoping for a return on Sunday.

The Spaniard said: "It's getting there. I'm training with physios and working hard going in the right direction."