David Moyes had warned that it would be more difficult.
The West Ham manager has spent months telling his players that the Europa League they cruised through would be a different beast this side of Christmas.
West Ham are certainly not out of this tie following a 1-0 defeat at Sevilla, but have been given a lesson in what progression will take.
The Hammers battled well and were equal to the six-time winners of this competition for the most part, but were undone by a smart set-piece which saw Munir hand Julen Lopetegui’s side a first-leg advantage.
Having urged his players to be more clinical following a wasteful display at Anfield. Moyes will have been disappointed with how his side passed up their chances here, Nikola Vlasic the most guilty.
The travelling fans can take pride in their side’s performance; West Ham certainly weren’t outclassed, just outthought when it mattered most by a side who are yet to lose to English opposition in this tournament.
Moyes was boosted by the return of captain Declan Rice from illness with the England international the one outfield change from defeat at Liverpool, replacing the injured Jarrod Bowen. Alphonse Areola, who has Champions League experience with Real Madrid and PSG, started in goal.
On top of Rice’s return there was more good news for Moyes ahead of kick-off as Sevilla, already without a number of first team players, lost their main threat in former Barcelona man Ivan Rakitic in the warm up.
The Croatian was replaced in the XI by Munir, who passed up a golden chance to open the scoring inside five minutes, heading inexplicably wide from Tecatito’s cross.
Sevilla were dominating the ball, though Moyes knows this sort of contest suits his side, who can be so dangerous on the break or from the odd set piece.
Both of those situations offered up chances early on, Michail Antonio firing into the side netting having barged his way through the Sevilla defence, before Vlasic sent a limp free header straight at Bono in goal from just five yards, West Ham’s best chance on the night.
West Ham are built on a solid backline and will need to show that if they are to make it through this tie into the quarter-finals. However, having already been given a warning with his early miss, Craig Dawson and Kurt Zouma left Munir in far too much space inside the box to receive a ball from the full-back Marcos Acuna.
It was another let off - with a ghastly effort from Munir sliding wide - but another warning that West Ham had to heed.
Minutes later and Youssef En-Nesyri, the striker West Ham had tried to sign just over a year ago, was allowed to head at Areola who saved with ease.
West Ham were causing problems at the other end themselves, with Bono forced to dive and send Vlasic’s low strike around the corner with his finger.
The Hammers had reached the break level having - Munir aside - countered Sevilla’s threats well, not cowed by the ferocious atmosphere being created by the Spanish fans behind Areola’s goal.
The noise was unrelenting from the restart once more but West Ham continued to push against it, Tomas Soucek forcing a diving save from Bono with a drive from Antonio’s lay off.
West Ham had stepped up their battle in midfield with Rice crashing in with some fine challenges to spring his side on the break. But as was the case at Anfield last weekend, the last touch seemed to be lacking. Sevilla were being tested right up until the final moment, when they were let off the hook too often.
The noise began to reach fever pitch as Sevilla recovered from the early scares and pushed forward, Areola again saving a header from En-Nesyri.
Sevilla were back on the front foot and putting West Ham under pressure, Fornals trying a cute ball at the back for Zouma which left the Frenchman in the lurch and resulted in a sloppy free-kick which proved their undoing.
Normally so proficient from set pieces themselves, West Ham were caught out by Sevilla’s sleight of hand - all in white pushing towards the near post aside from Munir who, left in space for a third time, hung back and finished first time into the opposite corner.
West Ham were well under the cosh for a long spell following the goal, pushing Moyes to send Said Benrahma on - with instant benefit. Within minutes of his introduction the Algerian slid a ball across for Manuel Lanzini, who was only prevented from scoring by a stunning Jesus Navas block which left the former Manchester City man needing treatment. West Ham were creating again, with Lanzini firing wide from the edge of the box moments later.
As is too often the case with Benrahma, however, that spell was short lived and soon West Ham looked too blunt again.
Moyes hopes to welcome Jarrod Bowen back to the fold for the all important second leg at the London Stadium next week, where West Ham still stand more than a half-chance of progression.
A week, however, is not a long time to return this side to their free scoring best.
