Gasperini and Retegui give Celtic much to ponder

Gian Piero Gasperini's side are unbeaten in this season's Champions League

With a resounding defeat by last season's Champions League runners-up Borussia Dortmund still fresh in the memory, the prospect of another away game against the winners of the Europa League is a somewhat daunting one.

In Atalanta, Celtic will face another opponent who can turn defence into attack in the blink of an eye and who score goals for fun - although, in the Italians' case, they do lose a few as well.

Despite a couple of high-profile departures and a lengthy injury list, the team that starts against Celtic on Wednesday will still feature many of the side that trounced German champions Bayer Leverkusen in Dublin to claim their first European trophy and just a second piece of major silverware in their history (who can forget the Coppa Italia triumph in 1962-63?)

Atalanta narrowly missed out on a double last season, losing to Juventus in their domestic cup final, while finishing fourth in Serie A.

They are not a traditional giant of Italian football, never having won Serie A, but in recent times they have gone from yo-yo club to serial European qualifiers and that is in no small part down to the appointment in June 2016 of Gian Piero Gasperini as head coach.

Gallus Gasperini

The word 'swashbuckling' comes to mind when trying to encapsulate the style Gasperini likes his sides to play.

The man who made his coaching reputation with Genoa but then faltered at Inter Milan has found a home in Bergamo and, after a shaky start, is revered for leading the club to their highest-ever league finish of third in 2018-19 then repeating the feat in the two subsequent seasons.

With that came Champions League football for the first time – this will be their fourth campaign among Europe's elite – and an increasing number of admirers for the attacking brand of football favoured by Gasperini. Catenaccio this is not.

Goals are almost always assured for those attending the Gewiss Stadium (the 0-0 draw with Arsenal was a rare exception), often at both ends, as care-free attack leaves space to exploit behind a high backline.

But one need only look back on the 3-0 demolition of Liverpool at Anfield en route to the Europa League final to realise this is a team with serious quality.

Missing stars, old and new heroes

Mateo Retegui has scored eight goals in 11 Atalanta appearances this season

Atalanta have had to deal with the departure of one of last season's key men in Teun Koopmeiners, the midfielder who joined Juventus for £46m, and the loss of main striker Gianluca Scamacca to a pre-season cruciate ligament injury.

The defence has been further hit by a series of injuries, the Bosnian Sead Kolasinac the latest of those.

Long-time servants such as Marten de Roon, playing as an auxiliary centre-back recently, and Mario Pasalic have stepped into the breach while the fans have a new goalscorer to adore.

Mateo Retegui, an Argentina-born Italian arrived in the summer for a pretty penny from Genoa and his delightful chipped finish against Venezia on Sunday made it eight in eight league games.

A penalty saved by David Raya in the opening Champions League game is the only blemish on his record thus far. Celtic beware.

And that is before considering the man whose hat-trick in Dublin made Europa League final history, Ademola Lookman.

With three goals at the start of this campaign, including one in the 3-0 Champions League win over Shakhtar Donetsk, the Nigerian will be keen to add to that tally on Wednesday.

Celtic were made to pay for their naive approach in Dortmund. A similar one in Bergamo could yield a similar outcome.