YOU only get one chance to make a first impression.

For Stefan Scepovic, that opportunity arrived at the weekend when he made his Celtic debut against Aberdeen.

The 62 minutes the Serbian striker was on the field didn't yield any goals. Indeed, he didn't trouble Dons keeper Jamie Langfield.

What Scepovic did do was impress manager Ronny Deila, who is already convinced all the time, effort and money it took to get him here from the Spanish side Sporting Gijon will be worth it.

If the return starts to flow in the form of goals in Thursday night's Europa League group stage opener against Red Bull Salzburg, all the better.

But Deila is realistic enough to acknowledge it will take time for Scepovic to get up to full speed and, more importantly, for his new team-mates to understand how he plays, the runs he makes and the service he requires to allow him to do what he does best.

He is very different from the strikers who, up to now, have been playing at the point of the Hoops attack.

Scepovic is a frontman who likes to play on the shoulder of his marker, whose job is made all the more difficult by the Serb's perpetual motion.

However, this movement can make it tough for team-mates to know where he will pop up next, and a number of his intelligent runs against Aberdeen went unnoticed and unrewarded.

Deila is confident this will be a temporary and short-lived blip, and is already a huge fan of the man who almost slipped through the Hoops net.

He said: "I like the way Stefan moves, and I like the way he is very calm. He is always thinking. I know that, when his sharpness gets better and once he knows his team-mates better, he will improve."

For the likes of Anthony Stokes and Leigh Griffiths looking on, Scepovic's style illustrates graphically what the manager has been looking for to complement the system he has been trying hard to introduce.

"Stefan is a very hard-working player, and that is very important for our team," said the Norwegian. "We need 11 defenders when we don't have the ball and 11 attackers when we do, and that's my aim.

"But, most importantly for Stefan, we need someone to lead the line and to put the ball in the net."

With John Guidetti also making his debut at the weekend, to a huge cheer from a support who have already taken the Manchester City loanee to their hearts, the international break has heralded a complete changing of the guard in attack.

Deila hopes the Serb and the Swede will be the final pieces in the jigsaw he has been building since he arrived from Stromsgodset.

And with Wakaso Mubarak still to take his bow, having returned too late from international duty with Ghana to figure against Aberdeen, there is even more fresh blood to be injected into the side.

The flying winger is in line to see his first action in the Hoops when they face Salzburg after Aleksander Tonev failed to make any real impression on his debut at the weekend.

He did, though, make plenty of headlines for what he is alleged to have said rather than what he did.

Deila would rather be preparing to test his players in a Champions League tie either tonight or tomorrow.

But, having failed to negotiate safe passage through the play-offs, it is on Thursday's Europa League opening group game that they must focus.

The extra couple of days' recovery from the efforts of the weekend will be welcomed.

"That's important," said the manager of the extra rest, with Wakaso, in particular, expected to benefit. "Wakaso had not even trained with the team until this week because of the break. That's why he was on the bench for all of Saturday's game."

The couple of weeks' breathing space between the draw for the Europa League group stage and the opening tie is in stark contrast to the fast and furious nature of the qualifiers and play- offs, when there was sometimes only a week between finding out who you were to play and actually going toe-to-toe with them twice in seven days.

A stickler for prep work and analysis, Deila and his backroom team have used the time well and will ensure all their players are fully briefed on what to expect when they get to Salzburg tomorrow.

The early season winning form enjoyed by Red Bull has started to unravel, with the Austrian champs losing their third game in a row at the weekend, 1-0 away to Wolsfsberger.

Their disappointing run includes the defeat to Malmo which saw their heavily-financed dream of reaching the Champions League crash and burn.

Like Celtic, they will aim to make amends in the Europa League, in which they are the top seeds in the group.

However, having failed to grab the millions on offer from the Champions League, Salzburg cashed in on their key attacker Sadio Mane, selling the Senegal international to Southampton for £10million hours before the window closed.

Without doubt, Salzburg are a weaker team without the 22-year-old who scored 45 goals in 87 games over the past two seasons. Deila has take every opportunity to try to identify where they may now be most vulnerable. He is an admirer of their quick-tempo pressing game. But, as an advocate of a similar style, he hopes he knows how to spike their guns.

"My staff have seen a lot of them," he revealed. "From the end of the Aberdeen game our focus has been on Salzburg."

With a mixed bag of experiences and results in Europe already this season, Deila would like to see a repeat of the way his side played in Maribor - but with the extra goals their play that night deserved.

"Of course, I would be very satisfied if we could do that," he confirmed . . . before going back for one more look at that dossier on Salzburg.