CELTIC were knocked out of the Europa League on Thursday night by Valencia, with the Spanish club progressing to the last 16 of the competition as comfortable 3-0 winners on aggregate. Brendan Rodgers’ side looked a lot better at the Mestalla than they did during the home leg of the knockout tie and had Jeremy Toljan not been sent off for the Scottish champions, who knows what could have happened.

But the fact remains that Celtic are out. While there’s certainly no shame in getting knocked out of Europe by a Valencia side that features the likes of Dani Parejo and Goncalo Guedes, the manner of the defeat - particularly Celtic’s performance in the home leg - will undoubtedly hurt for Celtic fans.

Rodgers is now closing in on three full seasons at Celtic Park and it is only right that fans question his record in Europe. Domestically speaking, Rodgers has unquestionably done fantastically well; by the end of this season, it would be little surprise if Rodgers had added a third successive Treble to Celtic’s trophy cabinet.

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And yet, European performances have often underwhelmed. There has been the occasional thrashing off of Paris Saint Germain and Barcelona, the odd slip-up in qualifying and, perhaps most worryingly for Celtic supporters, an inability to sustain a realistic challenge to qualify for the last 16 of the Champions League. So, the question is: have Celtic actually progressed in Europe under Rodgers?

The graphic above highlights the last three Celtic managers’ performances in the group stages and knockout rounds of the Champions League and the Europa League, and the results are enlightening. Rodgers’ points per game in Europe’s premier club competition is nearly half that of Neil Lennon’s, the last Celtic manager before Rodgers to have led the club against Europe’s elite. In short, Celtic are picking up nearly half as many points in the Champions League under Rodgers as they did when Lennon was in charge.

Rodgers does have a better record in the Europa League than either of his predecessors, but the question Celtic fans must ask themselves is whether or not this is in line with the club’s ambitions. Qualifying for the Champions League proper is the club’s stated aim in Europe each season, but if they cannot make an impact once they are there, should there be a greater focus on improving on Europa League performances?

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It’s true that football has changed, even since Lennon’s time in the Parkhead dugout, as the spending power of Europe’s top clubs has accelerated at an alarming rate. Some will say that this financial chasm that has opened up has left Celtic behind and that they cannot realistically compete with Europe’s top sides. But there can be little doubt that, whatever the reason, Celtic aren’t what they used to be in Europe.

It wasn’t too long ago that Celtic Park was considered a fortress and a difficult venue for any team to travel to. Clubs like Juventus, Barcelona and Manchester United all came to Glasgow and left empty-handed, and Celtic were always capable of stepping up a gear or two when they really had to. Since then, however, the intimidation surrounding Parkhead has evaporated.

Teams like Bayern Munich, PSG and Barcelona have all came to Celtic Park in recent seasons and left with all three points; understandably so, given the huge gulf in resources. But so have teams like Salzburg, Borussia Monchengladbach and Anderlecht, teams that Celtic should be aspiring to win against. Celtic’s home record beyond the qualifying rounds has been in steady decline, whether they have been playing in the Champions League or the Europa League.

Lennon’s Celtic averaged 1.75 points per home game in the Champions League back in 2012/13: that total has more than halved since. Last season, Rodgers’ side gained 0.75 points per home game - better than in his first season where the figure stood at a paltry 0.33, admittedly - but this is still a far cry from what the team were achieving under Lennon. Even Lennon's worst season in the Champions League was better than Rodgers' best.

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Even in the Europa League, this season’s points-per-game of 1.5 - the highest tally under Rodgers - is still lower than the 1.75 Ronny Deila achieved during his first season as Celtic manager. Supporters might argue that Deila faced an easier draw than Rodgers, but the fact remains: Celtic’s European results have been on the slide for quite some time.

For all the wonders Rodgers has worked in Scotland - and to reiterate, his success domestically is unparalleled - European performances and results remain something of a letdown from the Northern Irishman. Not only are Celtic struggling to improve on the European stage, they are actually regressing.

Fans defending Rodgers will say that Europe’s top clubs have pulled away from Celtic financially over the last few years, and that this is the reason for the downturn in form. This is certainly a factor, but Rodgers also deserves his fair share of the blame here as well. Whether it’s through the tactics he employs or the players he has recruited, Celtic are not the force they once were and Rodgers is ultimately responsible for this.