MARK Warburton and his backroom team have been methodically poring over the footage of the last two Old Firm matches.

While he says it doesn't take a "rocket scientist" to work out what went wrong between the shoot-out victory in last season's Scottish Cup semi-final and the 5-1 Premiership defeat at Celtic Park in September, he still has to get the precise chemistry of his team right or else today's BetFred Cup semi-final could explode in his face like the last one.

The first dynamic with which he has to struggle is his midfield, and the same equation which is played out on seven-a-side pitches throughout the land. How many experienced old heads does he need in there, compared to the dynamism and energy of younger men?

Read more: From scared youth player who could barely talk to being captain of Rangers - it's been some journey for Lee WallaceThe Herald: Rangers manager Mark Warburton

If the question going into the last Old Firm match was whether Joey Barton and Niko Kranjcar could both be accommodated in the same midfield, now people wonder whether Rangers can live without either.

With both veterans absent for differing reasons - Barton's dispute with the club has been well-documented, while Kranjcar suffered a training ground accident last week and will be out for two months - Warburton's hand has been forced.

It seems likely that he will name a midfield of Andy Halliday, Jason Holt and Josh Windass which boasts two of the three components which performed so admirably at Hampden last April alongside Windass who was one of the rare plus points from the rout at Celtic Park.

Read more: From scared youth player who could barely talk to being captain of Rangers - it's been some journey for Lee Wallace

“We have gone over aspects of last season’s semi-final where we did well," said Warburton. "And we look at the last game again Celtic and what did we lack? We lacked some energy and legs on the day. You don’t have to be a rocket scientist to work that one out. We didn’t play our normal game. We did lack some energy and dynamism, which was the hallmark of us last season, and that’s what we have to do."

While the Celtic team has largely been picking itself - the only issue may be freshness due to their Champions League endeavours - the selection dilemmas don't stop there for the Rangers manager. While Danny Wilson and Rob Kiernan produced an excellent performance both in possession and without it at Hampden last April, injuries, suspensions, and variance of form has prevented any real continuity in central defence this season. All four of his options have had moments this season where they haven't looked too clever.

While the likes of Moussa Dembele and/or Leigh Griffiths present stiff opposition, Wilson has been struggling with a quad injury and Philippe Senderos was dismissed last time out at Celtic Park. It could mean Warburton's best option is to stick with Kiernan, who was culpable for at least a few of the goals at Celtic Park in September, and Clint Hill, who turned 38 last week.

Uncertainty also applies in his interchanging front three, where another seasoned veteran Kenny Miller should perhaps be the most confident of selection. Barrie McKay, the scorer of a sensational goal at this venue in April, does a valuable job for his team and is likely to play, which leaves Martyn Waghorn and Joe Garner, the former Preston man who scored at Celtic Park in September, vying for the other place.

Perhaps the biggest problem, though, is how much Celtic themselves have raised their game since Tom Rogic's mis-kicked penalty gave Rangers the win last April. Only five of their starters from the match which sealed Ronny Deila's fate are likely to start this one, and while Brendan Rodgers also accentuates a pressing game, his team tend to execute it far more efficiently. While Jose Mourinho's rather agricultural tactics at Anfield on Monday night threw in a curve ball to defy Jurgen Klopp's Liverpool, it is admirable that Warburton has no intentions of altering his passing principles, even if Celtic pressed with such ferocity in September that his back four, Barton and goalkeeper Wes Foderingham ended up inviting pressure on themselves with passes along their own six-yard box.

"We didn't press enough the last time, that is for sure," said Warburton. "But this thing about rigidity of tactics. Because we don't go with three at the back, or don't go with two strikers, do people not think we move within the system? Am I going to go direct, long ball, 4-4-2, no I am not going to ever do that. Because it doesn't suit and it isn't the way the game should be played in my opinion. But there is always a way out. There has to be a man somewhere. Please don't take this the wrong way, and say I am comparing us. But I think people know how Barcelona play and it doesn't mean they can stop them."

Warburton's mantra is that it is good to talk, even if the reverberations are still being felt of the post-mortem after the last Old Firm match. “The players know most because they’re involved in the game," he said. "Ninety nine times out of 100, the first question I’ll ask at half time will be 'what are your thoughts gents?' "

There are ways to get your complaints across. "A couple of people said something in the office the wrong way," said Warburton. "That was interesting. Even [Wednesday] morning we had a little spat out on the field because players are passionate and they want to get better."

Garner, who saw his memorable Old Firm debut goal in September become a footnote in history, is one of those men who might be happier playing 4-4-2. But whatever happens this combative character feels Rangers must play with aggression.

Read more: From scared youth player who could barely talk to being captain of Rangers - it's been some journey for Lee Wallace

"It [the goal] was completely wiped out by what happened, but we went into half time 2-1 down and for the 15 minutes after half time we were probably the better side. It might not be the style of play we go with but personally I think you have to be aggressive in derbies. If you let top players have the ball and do what they want to do, they're going to hurt you."

As much as a historic triumph as that April win felt, even now the memories have a bittersweet quality, as Rangers couldn't go on and seal the deal. “Inside the club we knew the significance of that game and that win, because of where the club had been for four years," said Warburton. "But the record books don’t show we had a great semi-final and then lost the final. They show that we lost the final."