The initial excitement had hearts beating a little faster at Celtic Park last night but this was a Valentine’s date that brought bitter gifts.

If it had all started off so well with the disco lights lightning up a pulsating modern arena, their ultimate purpose seemed to be to shine a light on familiar insecurities. Defensive problems that have been Celtic’s concerning trademark in a European context came to the fore as the Parkhead side were complicit in picking at old wounds as their night and Europa League aspirations unravelled.

Valencia, with a goal either side of the interval, ran out comfortable winners but Celtic’s irritation will lie in just how easy they made it for their visitors.

Honduran left-back Emilio Izaguirre slept to play on Ruben Sobrino to set up Denis Cheryshev’s opening goal before Jozo Simunovic was caught out as Sobrino netted the killer second.

Izaguirre had started the game with Kieran Tierney still out injured but it was an arduous night for the Honduran who suffered greatly at the hands of Valencia. It will be a challenge for him to pick up the pieces from this performance.

Brendan Rodgers penned his programme notes in Spanish last night but in any language the gulf between where Celtic are and where they want to be is clear.

There was irony in the sight of Valencia’s Cristiano Piccini patrolling the flank, with Celtic keen to sign the player last summer before the Italian fullback left Sporting Lisbon for La Liga. But if the challenge is to find a balance of signing quality without upsetting the financial equilibrium – and Celtic’s annual wage bill sits at just shy of £60m – there has to be frustration too at some of the performances in a European context of players who seem too easily spooked into conceding possession.

In the early opening exchanges Celtic seemed to take their charge from an arena that was jumping.

There were just 90 seconds on the clock when the shout went up after Lato and James Forrest collided on the edge of the box and although the incident was waved on without incident, it seemed to be an indication of a Celtic side in the mood to take the game to their Spanish visitors.

Callum McGregor drove forward before unleashing a long range effort that was spilled by Neto with Forrest muscled out of the way as he pushed to collect the rebound.

But if the early minutes of the game showed a spirited side of Celtic, it dissipated as soon as Valencia drew the initial energy out of the game. And so much of when Valencia had joy came through Celtic making sloppy mistakes.

Indeed, the first real chance that Valencia carved came as Izaguirre, irked at a call going the opposite way he wanted, was still arguing the toss with the assistant referee when a cross was allowed to cause all sort of panic in Celtic’s defence.

Daniel Wass was first to get his head to the ball, drawing a smart save from Scott Bain who had to leap to his left to push the effort away.

It was an indication for Bain, too, that he had walked from a relatively comfortable few months in between the sticks to an altogether challenge of keeping the ball out of the net in the very different environment of the Europa League.

In ahead of Craig Gordon because of his calmness with the ball at his feet and his ability to see the game in front of him, there was a steep learning curve for the keeper as Valencia’s pressing made playing the ball out from the back fraught with danger.

At one stage Bain seemed to catch Scott Brown unaware with a pass to the midfielder’s feet at the edge of the Celtic box, with Brown then sending the ball back the way with Denis Cheryshev close to nipping in and taking full advantage of the mix-up.

Having come into the game on the back of a solid run of results and in fairly fluent form, there was a number of players who seemed to lose their composure with the ball at their feet with possession given away far too cheaply.

There was moment where Celtic seemed to find their feet again as McGregor combined with Scott Sinclair and sent Oliver Burke racing through on goal but Neto was quick off his line to smother the danger.

If Celtic thought they could get to the break and compose themselves, their game plan was shot when Valencia took the lead.

Daniel Parajo waited and waited before playing his pass through to Ruben Sobrino who broke through Celtic’s backline. As Celtic shouted for an offside flag, Izaguirre was shown to clearly have played Valencia on. Sobrino squared the ball across a deserted six-yard box for Cheryshev to tap the ball into the net.

Celtic tried to rouse a response with Sinclair and Forrest combining at the other end but any ambitions of forcing their way back into the tie were undone almost immediately after the interval.

Cheryshev turned provider this time while Simunovic took the turn of playing Sobrino onside. As Dedryck Boyata stood off, Sobrino volleyed into an exposed net.

Rodgers responded by putting on Timothy Weah and Odsonne Edouard for Sinclair and Christie. There were snatches of activity as Celtic tried to utilise their pace to haul themselves back into the game but by then the damage had been done.

If the second period felt like a long way to endure, the return leg next Thursday night in Valencia promises to be an endurance test.