PERHAPS the more pertinent question on the night when Celtic faced up to Cluj again for the first time since their Champions League exit at the hands of the Romanians was what precisely they had learned from that chastening experience. The answer was plenty.

Goals in either half from Odsonne Edouard and Mohamed Elyounoussi sealed a night of sweet revenge for Neil Lennon’s men, and here are five things we took away from the win…

CELTIC’S PRESSING GAME SUFFOCATED CLUJ

Celtic came haring out of the traps and successfully stifled the visitors in the opening half hour.

The high-energy pressing of the home side meant that the Romanians simply couldn’t get out, allowing Celtic to win the ball high up the park and pose a regular threat to Gledrius Arlauskas’s goal.

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It was always going to be difficult to maintain those levels, and with 15 minutes of the first half left Celtic did indeed hit something of a lull, but they got out of that opening spell with the lead they wanted, if a little disappointed that it was only the single goal from Edouard.

After the break, Celtic were more selective about when to stick and when to twist, but they had control of the game and made it difficult for Cluj to build up any sort of momentum at all.

LESSONS WERE LEARNED FROM HORROR NIGHT AT CELTIC PARK

The trouble with pushing as high and in as many numbers as Celtic did in the first half is that you risk leaving yourself open if your opponent can beat the press, and Cluj showed in the first meeting between the sides at Celtic Park that they are lightning quick on the counter.

That’s why Celtic assistant John Kennedy was permanently stationed on the edge of the technical area during the first half as he barked reminders to the Celtic defence and deeper lying midfielders to remember their responsibilities and to mind the shop diligently as their teammates pushed onto their opponents.

BROWN AND MCGREGOR PROVED THEIR POINT

This pair were two of the central figures in Celtic’s loss to Cluj in August, Brown for giving away a critical penalty with a moment of madness and McGregor for somewhat ludicrously being shunted to left-back on the night.

Both set out here then with a point to prove, and prove it they did as they ran the show from the middle of the park.

Brown was at his best, snapping into tackles while showing composure when in possession, while McGregor was like a man possessed as he popped up all over midfield as well as providing moments of quality when he got on the ball.

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This was typified with his wonderful defence-splitting pass that set Boli Bolingoli on his way to centre for Edouard to nod home the opener.

You can bank on it that Neil Lennon learned here too that McGregor is far too integral to how this team ticks to play at left-back ever again.

DEFENSIVE DUO DEVELOPING THEIR UNDERSTANDING

Continuing with the theme of key partnerships in this Celtic team, the central defensive duo of Christopher Jullien and Kris Ajer seem to be developing their understanding nicely, and will be delighted with the clean sheet here against a team that scored four on their last visit to Celtic Park.

They are still a work in progress, but they have the makings of a formidable pairing given their obvious physical attributes and their ability to dominate strikers, as evidenced here by the way they marshalled Mario Rondon, a player who proved a real handful in the meeting between the sides here previously.

If Lennon had these two players at the heart of his backline that night with Jullien fully up to speed, they may well have gone on to have a crack at Slavia Prague in the Champions League play-off round.

ELYOUNOUSSI GAVE A GLIMPSE OF WHAT HE CAN DO

The on-loan Southampton winger came into the Celtic side at the expense of Olivier Ntcham from the weekend draw at Hibs, and he justified his selection through more than just his first goal for the club.

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He does still look a little bit short of full sharpness, but he worked diligently in a defensive sense nonetheless and provided some moments of real quality when he got the ball in more advanced areas too.

His goal owed a little to good fortune, his shot from 18 yards taking a deflection off Andrei Burca before arrowing into the corner, but he made his own luck by the way he burst a gut to get up and support the break that was led by James Forrest.

His opposite winger laid the ball back to him, and he got his shot on target to claim the goal. A show of promise of more to come, perhaps.