It wasn't supposed to end like this.

As Emma Hayes made her slow procession across the Stamford Bridge turf, cutting a solitary figure in the driving rain, it was hard not to feel like the scriptwriters had somehow got it wrong. It was not so long ago that Chelsea were being tipped to win the quadruple; now it is only the Women's Super League (WSL) title that remains up for grabs for the Blues this term.

It is not the fairytale ending that so many had hoped the footballing gods would deliver for a figure who has become an undisputed icon of the women's game.

Hayes had said before Saturday's match that this, the chance to make history at the club's spiritual home, was all she had ever wanted. But as she took in the applause of the Stamford Bridge support for the final time as Chelsea manager following yet another chastening Champions League semi-final defeat to Barcelona, it was hard not to feel a sense of injustice about the fact her glittering tenure would not be crowned with a European triumph.

For the past 12 years, this team has been built on the legs of great players, from Ji So-Yun to Fran Kirby to Lauren James, but it is Hayes' heart and mind that has carried them this far. It was Hayes who, in the early years of her Chelsea career, had to clear the water from the pitch at Wheatsheaf Park in Staines so that her team's WSL clash with Liverpool could go ahead.

No such exertions were required from the Chelsea boss today, with the pitch having been immaculately prepared for the occasion by the club's groundstaff. But all of this - the noise and the colour of the 40,000-strong crowd - was born from her drive and ambition, from her complete unwillingness to accept anything less than the best for her side.

READ MORE: Emma Hayes says Chelsea were 'robbed' by 'worst decision in Champions League history' against Barcelona

READ MORE: Chelsea suffer Champions League heartbreak after controversial semi-final defeat to Barcelona

With that in mind, it feels especially gut-wrenching that Chelsea faltered when they were in touching distance of the promised land. Last weekend's 1-0 first-leg win at the Estadi Olímpic Lluís Companys had put the Blues on the brink of sporting immortality.

They were 90 minutes away from Bilbao and the chance to exorcise some Champions League ghosts before Hayes swaps west London for the shores of the USA, where she will become manager of the women's national team in just a few short months time.

But the fact Erin Cuthbert's stunning strike had propelled Chelsea to victory in Catalonia only served to intensify the belief that the European champions would have an even greater appetite for success in the second leg, with Hayes herself insisting that her team would have to be "perfect" in order to dethrone the "best team in the world".

Certainly, on Saturday afternoon, there could be no quarrelling with Barcelona's status as the benchmark for footballing excellence. Jonatan Giraldez's side started strongly, outranking their hosts in almost every conceivable metric.

As the rain hammered down in SW6, Chelsea were made to toil and chase and charge down. They were made to scrap and suffer and, when defender Jess Carter emphatically lashed an early clearance into the stands, the home fans greeted it with the same fervency they would normally reserve for a goal.

Even they knew that it was never going to be pretty - it didn't have to be. But, when Ballon d'Or winner Aitana Bonmati's deflected effort squirmed into the back of the Chelsea net after 25 minutes, the scale of the Blues' challenge really started to hit home.

Barcelona had most of the ball and looked threatening on every attack. But, strikingly, it was the hosts who had the better chances, with Melanie Leupolz crashing an effort against the crossbar from six yards out and Catarina Macario forcing a fine fingertip save from Catalina Coll.

And, when the players took to the pitch for the second half, it felt like it was only a matter of time before the Barcelona net bulged. When Sjoeke Nusken's strike crashed off the post, prompting Hayes to bury her head in her hands, it seemed like a Chelsea goal was inevitable.

Inevitable, that was, until centre-back Kadeisha Buchanan was controversially handed a second yellow card for an alleged foul on Barcelona captain Patri, reducing the hosts to 10 players and handing all of the momentum to Giraldez's side. "I thought that was the worst decision in UEFA Women's Champions League history," Hayes told reporters after the game. "I’m gutted for (the players). We were robbed."

It was the latest in a long line of post-match diatribes from the Chelsea boss, who has provided the press with plenty of headline-worthy soundbites in recent months, at times landing herself in hot water with her unflinching frankness

But, in this instance, while she could be accused of hyperbole, it’s hard to refute her claims that Buchanan’s dismissal drastically altered the complexion of the game. And Chelsea's misery was further compounded when they were on the receiving end of what Hayes branded "an equally soft decision", with the referee pointing to the spot after Bonmati was felled inside the penalty area.

From the moment the ice-cold Fridolina Rolfo dispatched her spot-kick, it was clear that this story was only going to have one ending. The cavalry was called for, with captain Millie Bright coming off the bench to make her first appearance in more than five months, but it was too little, too late for the Blues, who might well be starting to fear that Hayes' last dance is turning into a draining, dizzying waltz.

But, with just four games of the WSL season still to play, these players must somehow summon the strength to finish the campaign with a flourish, rather than letting their manager's swansong become a forgettable footnote in the most memorable of Chelsea chapters.

For Hayes, there will be no grandstand finale, and the manner of her latest European exit will continue to rankle for some time. But, even as the Chelsea boss trudged down the tunnel on Saturday night, the crowd could still be heard chanting her name - proof that, when the pain of this defeat has settled, her legacy will continue to echo within these walls for years to come.

All of this season's UEFA Women's Champions League fixtures are broadcast live DAZN and you can register for free here. The second leg of Lyon vs PSG is also free to watch here.