Fine margins defined this football match. Just a few centimetres, in the key moments. As OL Lyonnes owner Michele Kang celebrated on the pitch, arm-in-arm with her players with the Arsenal squad’s faces a picture of total dejection, those tiny differentials will have felt wider than the Rhone which runs through the city. Arsenal’s reign as European champions has ended.

Up in the top tier, overlooking the scene with almost a bird’s-eye view, around 600 Arsenal fans had reason to be proud but ultimately were despondent. It was barely the thickness of a French baguette that had kept Jule Brand onside when her late winning goal for OL Lyonnes was reviewed by the VAR. In similarly agonising fashion, Arsenal’s Daphne van Domselaar stepped off her line just too early when initially saving a first-half penalty, which Wendie Renard retook and scored. But if those travelling Arsenal supporters were reflecting honestly, Lyonnes were worthy winners.

Invigorated by the return to match fitness of Melchie Dumornay – who missed the first leg through injury but whose splendid second-leg performances exemplified why she deserves to be one of the favourites for the Ballon d’Or – as well as Lyonnes’ returning left-back Selma Bacha, the French side looked transformed compared to their uncertain first-leg display.

As harsh as it may seem to criticise a team that were so close to another European final, Arsenal’s defeat now enhances the prospect of a trophyless season, who were disappointingly knocked out of the FA Cup by Brighton in April and were also knocked out of the League Cup semi-finals by Manchester United in January.

It would be wrong to say Arsenal have gone backwards since winning last season’s Champions League – they look just as strong, if not stronger – but Lyonnes had improved markedly. That is no surprise following their significant investments in their squad last summer. The capture of Brand from Wolfsburg is paying off in spades and several of their other summer signings, not least the 18-year-old prodigy Lily Yohannes and the ever-reliable former Chelsea defender Ashley Lawrence. Lyonnes’ squad was strong enough to enable them to leave Marie-Antoinette Katoto, France’s starting central striker, on the bench. That is, as the locals might say, formidable.

Arsenal have not exactly been shy when it comes to spending, most notably breaking the £1m barrier last year to sign Olivia Smith, and snapping up Chloe Kelly. This season Smith has excelled but SSaturday’s game showed that she still has a way to go to catch Brand and Kadidiatou Diani.

Smith’s time will surely come. Brand and Diani’s clinical finishes won this tie and, for now they, are setting the standard on the wings in this competition.

A January addition for Arsenal, Smilla Holmberg, did impress off the bench and provided a fine assist for Alessia Russo’s ninth Champions League goal of the season. Arsenal are widely considered as the favourites to sign the Bayern and England midfielder Georgia Stanway and Spain full-back Ona Batlle from Barcelona this summer, so they look set to be stronger next term.

What Saturday’s defeat did expose was a distinct vulnerability at set-pieces. And not for the first time. Arsenal were also undone by a Brighton corner in the FA Cup. Manchester City similarly scored from a corner in October 3-2 win in the WSL, a pivotal game which – as it stands – is proving key to tipping the balance in the title race. In September, a 94th-minute Aston Villa corner saw Arsenal draw at home, one of the only instances of Renée Slegers’ side dropping points in the league this term. In competitions where the margins are so fine, defending set-pieces is a vital area in which Arsenal must improve.

Asked about set-pieces during her post-match press conference, Slegers replied: “Lyonnes is a very, very strong team on set-pieces with their length, physicality and the quality of delivery, and they’ve scored a lot of goals from set-pieces and we knew that, so it’s frustrating to concede in that way but it’s also one of their super strengths.”

Defensively, Arsenal have actually improved overall this season and have by far the best defensive record in the WSL this term, conceding an average of 0.67 goals per game in the league, significantly down from the 1.18 goals per game the conceded last season. That has helped them be on course to surpass the WSL points tally they accumulated last term, which is partly why now is not really the time for any kind of eulogy for Arsenal.

The Gunners are not in decline but Lyonnes are simply a better football team at the present time and that will be a horrible feeling for Arsenal to stomach on this bank holiday weekend. There is still a glimmer of hope for Slegers’ side domestically but they need a favour from elsewhere and will need to win their own games, none of which look easy, starting with Wednesday’s testing trip to Brighton. A run of seven games in 20 days will test the strength of Arsenal’s squad to the limits.