Celtic v Rangers RTE1, BBC1 (12.30) Celtic manager Martin O'Neill yesterday warned his quadruple-chasing squad they could not afford to lose today's Old Firm showdown.

Rangers will open up a nine-point gap over their arch-rivals at the top of the Scottish Premier League if they can win at Parkhead.

Celtic would still have a game in hand, but O'Neill believes defeat today would see the Ibrox men open a "significant gap" in the race for the title.

"The lads are doing fine in all competitions and the game is of great significance," said O'Neill.

"We are coming into the last nine or 10 games of the season and the chances to slip up and then get it back again over a couple of other fixtures is becoming less and less.

"It is very important. It's up to us tomorrow to try and win the game. It's an opportunity for us against our rivals and if we were able to win the game it would close the gap with us still having a game in hand.

"If Rangers were to win the game it would open up a significant gap. so it's important for us and it's a game we will never treat lightly.

"With the number of games left it is very important for us. I expect both sides to drop points they might not be expected to, purely because as it gets towards the end anything can happen."

O'Neill will still be without Henrik Larsson after ruling out the possibility of the prolific striker making a surprise return against Rangers.

The Swede is recovering from a double fracture of the jaw, but while his rehabilitation is going well he has still not been allowed to join his team-mates in training.

"On Sunday it will be four weeks since he got the injury and the surgeon wants him to stay without any physical contact," O'Neill revealed.

"I don't want to put a timescale on it, but he's doing fine at the minute.

"He's not done any physical work at all and I would have thought it would be a miracle if he was to play."

O'Neill is more immediately concerned about his leaky defence. He conceded that if they continue to make mistakes today it could signal the end of the club's championship ambitions.

They have conceded five goals in their last two games and six to Rangers this season, and the Celtic boss will not tolerate any more lapses.

But whatever his concerns about his defence, O'Neill has promised all-out attack even though he reckons Rangers are as good as any side in Europe at exploiting weaknesses.

"We are going to try and win the game tomorrow," he insisted. "We will be going all out to win the match.

"But if at any stages in the game we leave gaps Rangers are as good as any side in European football to exploit these gaps."

Rangers manager Alex McLeish admitted that a win for his side would make life difficult for Celtic between now and the end of the season.

But he warned that neither side can be complacent about the impact the other 10 SPL sides could have in deciding who wins the title.

McLeish said: "We certainly want to keep our lead intact at the top of the table but it is disrespectful to the rest of the SPL to suggest the match is a title decider.

"There is still plenty of football to be played after the Old Firm game. We would be in pole position for the title if we win but, if Celtic get the points, it should make things very interesting."