WHEN you are playing against Hearts, it might be expected you shuffle the pack to ensure you play your strongest hand.

So it is that Neil Lennon will be searching for aces as he aims to lift the pot at Tynecastle this weekend.

It will take a lot to trump Sunday's performance against St Johnstone.

And with Emilio Izaguirre the latest name to join an injury list which already contains James Forrest, Mikael Lustig, Beram Kayal and Steven Mouyokolo, the manager has a difficult team selection ahead of him.

So it is understandable Lennon is delighted to have the very versatile Charlie Mulgrew back in contention for a starting place for a game which, while it pits top against bottom, always brings the severest test of bottle for all taking part.

It's not just Mulgrew's ability to play a number of positions and his expertise at delivering from set-pieces which makes him a key man in Lennon's plans.

The 27-year-old's temperament and experience are every bit as important, especially with new Bhoys being bled into the side.

These qualities were badly missed as Celtic crashed out of the William Hill Scottish Cup to Aberdeen.

And, even though the Hoops got back on an even keel against St Johnstone to re-establish their 21-point lead in the championship, Lennon firmly believes the big man's influence was noticeable by its absence.

"We have missed him, certainly, at times, in terms of our composure and class," said Lennon. "Having said that, against St Johnstone, Nir Biton brought a lot of that composure to the team."

The Israeli had his best game to date at the weekend, putting his naive showing against Hibs on his previous start behind him.

Lennon appreciates the young man needs time to settle into a new environment, but sees clear signs of progress.

"I think that is Nir's best position, and something we will work on for the future," said Lennon, after watching the 22-year-old anchor the side. "He has struggled a bit to reach the pace of the game. But on Sunday he was outstanding and read the game brilliantly."

Biton provided excellent cover for Efe Ambrose and Virgil van Dijk at the heart of the Hoops defence, one of the reasons Fraser Forster did not put his hands on the ball until midway through the second half.

Indeed, the man who was equalling Bobby Clark's record of 12 consecutive clean sheets in league games - and who only has to survive 31 minutes at Tynecastle to surpass the Aberdeen's legend's period without conceding - had just one save to make all game.

That came when Nigel Hasselbaink's shot deflected off the foot of Ambrose, forcing the big man to show he was not only fully concentrated, but lithe and agile.

"He made a brilliant save towards the end of the game," acknowledged Lennon, who considers Forster to be one of the all-time great keepers in Celtic's history.

"The ball was moving one way, and he was moving the other, but he managed to stick a leg out and keep the record intact.

"He will be delighted with that. But there are a lot of players who can be pleased with their contribution against St Johnstone."

And a lot who will be looking to retain their place against Hearts. However, it is a different game on a different ground, with a playing surface much tighter than the huge expanses enjoyed at Celtic Park.

Lennon was denied any natural width at the weekend due to the injury to Forrest and the fact Derk Boerrigter was not deemed ready to start.

The Dutchman has taken one step forward and then two back in his attempt to push his way into Lennon's team.

But, like Amido Balde and Teemu Pukki, who also arrived at the club last summer, the remainder of this season will be the proving ground for him.

For Boerrigter, there would be few bigger tests than intimidating Tynecastle, and Lennon admits giving him a rare start is already occupying his mind.

"That's something we will look at this week," confirmed the manager.

"Derk is fit and ready to play, but the team has been playing so well it has been difficult for him to break into it.

"He got another 20 minutes on Sunday, so, when called upon, he will be ready."

With yet another lunchtime kick-off, everyone selected will have to be raring to go.

While such timing can cause logistical problems for supporters, especially those travelling from outwith these borders, Lennon is not prepared to allow early starts to be used as any excuse for performances which do not meet the high standards he demands.

His players were up and at 'em on Sunday against Saints and Lennon said: "We are used to these early kick-offs.

"But in the context of last week, it was important we started the game well and got the team entertaining. I think we got all of that.

"Our attacking play was superb. We got another clean sheet, and our midfield was very, very strong. St Johnstone are a good side, and are hard to break down at times.

"But it was a performance which made me very, very happy. We were all hurting after the loss to Aberdeen.

"It was a difficult couple of days after going out of the cup. But that's football, and that's the pressure and expectation you have to live with here.

"You saw the way they played on Sunday and the way they have played in previous weeks, and you realise that, against Aberdeen, it was an aberration on the day.

"But we have got to put it behind us. And I think, on that performance against St Johnstone, they have.

"I also believe there is plenty more to come from this team."