Celtic headed to Valencia after what many claimed was a title-clinching victory over Kilmarnock at the weekend.

It seemed no matter where you walked in the beautiful city of Valencia, a chorus of "Scott Brown won the league at Rugby Park" could be heard by the cheery visiting faithful.

Speaking to many in the city who were going to the game (and the many who didn't get a ticket) one phrase stood out: "Hope rather than expectation."

Partly, that was down to the venue. The Mestalla stadium. One of the great European football amphitheatres.

It seems the perfect symbol for the team of Valencia. A historic pillar of Spanish football, renowned across the globe and steeped in history and success.

You only had to look to manager Marcelino's side's results in the Nou Camp and Old Trafford and even the first leg at Celtic Park to see they're a class above the Scottish champions.

But as thousands of Celtic fans greeted their players off the team bus with heroic applause, there was a sense of optimism in the air.

As the team news filtered through, fans learned that Brendan Rodgers had opted for five at the back with two wing-backs. It seemed a sensible approach against a side who've only tasted defeat four times this season.

Once the formalities of the wannabe-Champions League theme song and team photos were out the way, it was time to get down to business.

It's only when you sit in foreign stadia on European nights you realise just how special Celtic Park and Ibrox are for electric atmosphere. Nothing against the Black Bat, but the atmosphere in the Mestella lacked crackle, with the home support expecting a gentle and cosy affair.

If that was the case, they were quickly reminded of the contest by Celtic's dynamic and positive start.

Energy, movement, pace - everything the Scottish champions needed in the first leg. The biggest compliment was the jeers from the home support as they feared this tie was about to burst back into life.

And how different the game would have been but for Jeremy Toljan's ordering off, which in Rodgers' words "took the game away from us".

That incident highlighed again the main failing of Celtic. Under no pressure, continuing to opt to play out of the back to suit Rodgers' philosophy. One mistake leads to a swarm of Valencia players and the referee has a decision to make.

Across the 180 minutes of this tie, three errors led to three goals and that's what would have frustrated the Celtic manager.

Even when down to ten men, Kristoffer Ajer had the chance to put Celtic ahead with a header and put it over. It was a chance you'd think would have been scored had it been presented to the opposition.

Inevitably, Celtic's defence was broken down and Kevin Gamiero put the tie to bed.

But what stood out was that, despite their elimination, the near 3000-strong away support didn't stop applauding until their team was up the tunnel.

Even in the post-match mixed zone you could barely hear the players for the thousands of fans hailing their team onto the bus.

The one underlying issue from Celtic's away European performances this season has been their defence.

Careless passing and loss of concentration is fine in the Premiership where they won't get punished as much but what European competitions do more than any other is highlight your biggest weaknesses.

Unless Celtic eradicate the defensive errors which have cost them dearly across this European campaign then Celtic fans may have to get used to going to these games in hope rather than expectation.