Scottish FA Cup fourth round Hearts v Celtic: Celtic manager Martin O'Neill will ram home to his stars the importance of keeping their cool against Hearts in the red-hot atmosphere of Tynecastle today.

Only a Stilian Petrov goal separated the two sides in the Scottish capital last month, but a controversial incident involving John Hartson left a nasty aftertaste with their opponents.

The Welshman, who is a doubt for the trip to Edinburgh with a back injury, left Hearts defender Andy Webster needing treatment after the pair clashed off the ball.

His manager backed him over the unsavoury flare-up, but he has attempted to take the sting out of the tail of today's Tennent's Scottish Cup fourth round.

"I should imagine that it would be fiery regardless of what went on before," said O'Neill. "A lot has been made of the John Hartson incident, but it is always a big occasion and a big game.

"We want to win the game and we want to do well and we want to stay in the Scottish Cup.

"In some of the games we have tended to press on the point of discipline. In big matches like this, you have a better chance with 11 players on the field rather than 10 or nine.

"That is the point I will be trying to press, but I know in the heat of the battle things can happen. But I would hope that they would get the message that we have to try and keep a bit of discipline.

"This game is always big and always has a hostile atmosphere. I'm hoping that it will be played in a good spirit and in the correct manner."

Celtic are preparing to embark on another European adventure, but O'Neill insists the Scottish Cup still holds a special place in his heart after his first season's success.

"Of course, every match in this competition is a glamorous game if we are involved in it right to the end of the season.

"It is the first week in February, but the point is I would love to go back to Hampden Park, no doubt about it, and I'll be really disappointed if we lose."

Hearts head coach Craig Levein will shake O'Neill's hand before the game to show there is no lingering animosity between the two clubs after last month's spat.

"I don't have a problem with Martin, we always do shake hands before every game," Levein said.

"I see him before every game and I invite him into the office as normal afterwards. There's been a lot of nonsense printed recently about 'powder kegs' and 'bad blood' between the teams.

"Of course, it will be competitive but I don't see that there's any bad blood between the two clubs."

Hearts striker Mark de Vries, who has suffered all week from a stomach bug, is making progress and Levein is hopeful he'll make it.

Midfielder Phil Stamp, who was floored by the same bug, has made a full recovery and Neil MacFarlane has recovered from an infected foot.

Midfielders Scott Severin (groin) and Steven Boyack (stomach) are both out.