BIG game, big consequences. It might be international week, but there is no doubt which fixture will already be occupying the minds of a great many football fans across the country. And indeed, around the world.

Celtic’s visit to Ibrox to face Rangers has been circled in red pen ever since they went top of the Premiership table by blowing their great rivals off the Celtic Park pitch back at the beginning of February.

In the period since, they have increased that advantage to three points, and so will travel across Glasgow next Sunday knowing that a win - given they also have a handily superior goal difference - would go a long way towards wresting back the Premiership title they lost so spectacularly last season.

They also know that a defeat, while far from fatal to those hopes, would be a body blow, and would not only open the door to Rangers but see them seize back the momentum that has been in Celtic’s favour since the last Old Firm meeting.

So, Celtic manager Ange Postecoglou isn’t for playing down the ramifications of what is to come in Govan next weekend.

“It’s a great challenge for us,” Postecoglou told Celtic TV.

“I think in the first game there, we didn’t get the result we wanted, but I thought our performance wasn’t too bad.

“It was a pretty tight game, there wasn’t a lot of chances for either side. They took theirs, we had a couple that we didn’t take.

“There’s no doubt it’s going to be a great occasion. You want to go into these games firstly on good form, which we are, and knowing that there’s big consequences to the outcome.

“It’s a great position for us to be in and I know the players will be looking forward to it.”

Postecoglou would certainly settle for a similar start to the game next weekend as his team produced in that last meeting at Celtic Park, with an early Reo Hatate goal and then a quickfire salvo from the Japanese midfielder and Liel Abada towards the end of the first half putting Celtic out of sight by the interval.

It might not be as straightforward on enemy territory this time around, a fact that Postecoglou is keen to impress upon both his players and supporters.

“Look, it just depends how the game goes,” he said.

“We definitely want to bring the same sort of energy and intensity, we try to do that home and away.

“The key to the position we are in at the moment this year is because away from home, we are still taking the game to the opposition and we’re still being very aggressive with our approach, which I think has helped us win a lot of games away from home.

“So, that won’t change, but you just don’t know what the opposition will bring.

“For us, again, we’ve been really good at overcoming the challenge that is before us, so whatever that may be in that game, hopefully within our football we can find the solution.”

Celtic’s cause will be aided by the return to fitness of David Turnbull, who made his comeback from the hamstring injury he picked up in December’s League Cup Final as a late substitute in last week’s win over Ross County.

That could be a pivotal factor not only in next Sunday’s game against Rangers, but in the title race as a whole, according to Postecoglou.

“Dave was real important to us, he played a lot of football,” he said.

“Probably in the end that’s where the injury got him. We didn’t have a big squad at the start of the year to call upon, and he was one of the ones who carried that load.

“He did it magnificently, scoring goals, creating goals, working really hard for the team. It was a shame for him, because I thought that he was in for a really big season.

“He’s had to work hard in rehab, which hasn’t been easy, to get back. So, to have him available now is great for us and great for him as well, because he’s been a key contributor to our season.

“There’s nothing worse than seeing a player who has offered already so much, and has more to offer, not being able to contribute.

“So, it’s great to have him back, and I’m sure he’ll be key for us in the last bit of the season.”

What makes Turnbull’s return all the more timely is the injury to another of the creative presences that operate behind Celtic’s frontman, with Tom Rogic having to miss out on Australia’s World Cup qualifier against Japan this week.

Rogic was forced off in that win over County after a hefty challenge from Kayne Ramsay that saw the defender red-carded, and he is a major doubt for the game against Rangers as a result.

“We’ll see how it all transpires,” said Postecoglou.

“Unfortunately he couldn’t go back and represent his country, which was disappointing for him.

“He’s still sore. He probably won’t train this week, so we’ll just assess how he goes in the week leading up to the next game.

“Suffice to say, he was pretty sore after it. It probably could have been a hell of a lot worse, but at the same time, it’s enough to keep him out in the immediate term.”