Early in the summer transfer window, much of the focus around Scottish football centred on the business Celtic were doing in strengthening their frontline and the amount of money committed to making it happen.

Right now, though, it is starting to look like the late splurge from Rangers on beefing up their options in attack during the final week of trading – while their arch-rivals across the city of Glasgow nodded off at the wheel – might be what ends up making the difference in the battle for the Premiership flag.

Camilo Duran, a £5.5million arrival from Qarabag, has been a success at Parkhead. Haissem Hassan brings undoubted excitement and trickery on the wing, although there is still some work to be done on justifying his prospective £9million fee.

The less said about £11million club record signing Kasper Hogh, the better. Radiating personality when he was first brought in, the Dane has looked progressively more bereft of confidence as the weeks have gone on.

In terms of what constitutes Celtic’s best mix up front, it’s not quite clear. Despite starting off at right-wing, Duran probably plays through the middle in their strongest line-up with Hassan on the right.

Maybe Jota will fill the role on the left in time, although the length of his absence through injury remains an obstacle. Maybe it’ll be Callum Osmand. The one thing you’d put money on is that it won’t be Sebastian Tounekti.

Benjamin Nygren is back scoring goals in a supporting role, of course, but the questions over whether he is a man to absolutely hang your hat on when it goes into the trenches remain.

At Rangers, however, certain things became evident through the murk – and occasionally biblical rain that left Edmiston Drive flooded post-match – as Derek McInnes’ side got back to winning ways with a four-goal hosing of St Johnstone yesterday.

Their front four reeked of danger. It’s the strongest front four McInnes has. And everything points to it getting stronger and stronger as fitness improves, game time increases and understandings and relationships build.

Some of the interplay involving Kevin Kelsy, Ryan Naderi, Badredine Bouanani and Kim Min-su during an excellent first half, in particular, was just lovely to watch.

They made it difficult to believe that the rock-bottom moment of Conference League qualifying defeat to the horrendous Jablonec on penalty-kicks – a result which really did place Derek McInnes’ position as manager in jeopardy – was only two months ago on August 27.

That evening, Daisuke Yokota, currently out injured and not exactly missed, started on the right. Djeidi Gassama was on the left, Naderi operated through the middle and Tochi Chukwuani was endeavouring to support from midfield. The whole thing was just a shambles.

What Rangers present now as an attacking force is simply chalk and cheese. Naderi is not suited to being the main man up front. He has struggled there throughout the campaign. At the start of the season, he was having a hell of a time.

As the secondary striker, though, he has come into his own and four goals in four games of late – including a winner at Parkhead – are the perfect proof. He has technical talent, an unselfish quality in key moments coupled with an ability to pick out team-mates and a lovely knack of being able to read things and get himself in the right place at the right time, just as he did when scoring Rangers’ all-important second after visiting keeper Toby Steward had spilled a shot.

This is Naderi’s best position. And when Rangers have everyone fit, this is where he ought to play.

What must please McInnes tremendously is that he really does appear to be getting on the level with centre-forward Kevin Kelsy, whom he set up for the opening goal with a great pass after an even nicer run.

He laid another goal on a plate for the Venezuelan just before the end of the first half as well, but the eventual shot was saved.

There remain imperfections in Kelsy’s game, which is to be expected with a 22-year-old straight out of the MLS and settling into an entirely different way of playing. However, there’s lots to be happy with when it comes to the big striker. He’s got off the mark quickly and now has four goals to his name including one against Celtic, always important.

His head looks to be in the right place and there is clearly a game intelligence there. McInnes made mention of it in an interesting way after the final whistle when talking about how he gets ‘good separation’ between himself and the defender in the area.

It’s true, though. He has a natural ability to move into space, as he did when scoring the third after a Min-su corner had hit off Manny Fernandez before falling his way. He works hard, too, and looks to have the right attitude.

Of all the attackers, Min-su was the pick. Forget the stuff about him having no goals and no assists in nine games. At just 20 years old, he’s a player, as they say. And he was involved in all three of the goals that tied this game up before substitute Chukwuani pitched up with a late effort to put a shiny blue bow on top.

Gassama has remained in the first-team shake-up since Jablonec and produced some decent performances, but he has to be Plan B on the left behind the South Korean. He isn’t in the same league as the one-time Girona player, an £8.5million arrival around the time of the Jablonec farce.

Naderi fills that role behind Kelsy, whose £9million signing from Portland Timbers at the end of the window showed real ambition, when Rangers are at their strongest. And  the St Johnstone game was evidence of how much Min-su can offer when out wide. His pass to Naderi ahead of Kelsy’s opener was imaginative, inspired and superbly executed. He worked the flank well throughout and simply shone.

Bouanani, a deadline-day recruit alongside Kelsy, started off like an express train on the other side before fading, but the Algerian, on loan from VfB Stuttgart, looks like he’s going to get people off their seats big-time when he’s fully up to speed. He brings the ability to run at opponents, beat a man and get into good positions.

What was most exciting about these four guys is that they all linked up with each other at different periods to create opportunities in this game. There’s a compatibility about them all that should become reinforced the more they play together.

The only drawback for McInnes from this encounter is that his side, for all the threat going forward, still went into a dwam at the start of the second half. As in their recent home win over Kilmarnock and last weekend’s 2-2 draw at Dundee, there are moments when they switch off a little, when the pace drops, when the collective body language doesn’t look as good as it ought to be.

It happened in the first 15 minutes of the second half here, when the game was 1-0 despite Rangers having created enough chances to win three games. There had been a warning late in the first 45 when Josh Fowler was sent clean through by Jamie Gullan and fired a poor effort into the side netting.

It wasn’t heeded, though. After the restart, Saints created a handful of opportunities in short order with sub Kai Fotheringham – later red-carded for a foul on Nico Raskin – volleying wide, Gullan being denied by Dujon Sterling, Ivor Pandur saving a long-range shot from Enes Alic, Bozo Mikulic putting an effort just off-target and Liam Smith then seeing an effort from a good position parried by the keeper.

Rangers rallied and Naderi scored at a good time to make it two, but it was a worrying period for McInnes. It is happening way too often and will be punished at difficult venues such as Tynecastle, where the team will be on Wednesday night.

The Ibrox outfit played such lovely stuff at times yesterday that it would be churlish to make too much of that lull, but it is something that clearly needs to be looked at, worked on and eliminated.

With a front four that can get the veins pumping the way they did in this affair, all kinds of things will be possible if others can just stop the rushes of blood to the head.