The Champions League remains the Holy Grail for Paris Saint-Germain, but Lady Luck seems intent on keeping it out of their reach.

Neymar's first-half winner against Saint-Etienne in Friday's Coupe de France final delivered a 1-0 victory and a third trophy to the PSG cabinet, and a fourth domestic prize will follow in seven days' time if Thomas Tuchel's side can defeat Lyon in the last ever Coupe de la Ligue showpiece.

But continuing to conquer France is not the MO for Tuchel, for he was brought to the French capital in 2018 to rule the continent too.

Champions League success has forever eluded PSG, despite their Qatari owners assembling a squad that remains the envy of most of their rivals.

Indeed, in the first two years since Neymar and Kylian Mbappe were brought to Paris at great expense in 2017 - the last 16 remained the hurdle they could not clear.

There was a mitigating factor in both years - the loss of Neymar to an untimely injury.

Between the first and second legs against Real Madrid in 2018, the world's most expensive player fractured his metatarsal, prematurely ending his domestic season in February as PSG suffered a 5-2 aggregate loss to the eventual Champions League winners.

Last year it was an ankle problem that sidelined Neymar as Manchester United completed an improbable comeback at the Parc des Princes when Marcus Rashford's penalty sealed a triumph on away goals.

This season it was supposed to be different. PSG had already cleared the last-16 hurdle, showing mettle many thought they may not possess by beating Borussia Dortmund despite losing the first leg.

Pre-lockdown Neymar and Mbappe were fit and firing. PSG would stroll into Lisbon in August as the freshest team as a result of the 2019-20 Ligue 1 season being halted in March.

The draw provided cause for optimism too. Real Madrid, Manchester City, Barcelona and Bayern Munich were all on the other side. Beat Atalanta in the last eight on August 12 and only RB Leipzig or Atletico Madrid would stand between Tuchel's men and a first final.

But just as the path to the Holy Grail appeared to be clearing, PSG stumbled upon a roadblock on Friday that may prove insurmountable.

As Mbappe surged forward, a first-half lunge from Saint-Etienne captain Loic Perrin ended his progress, the PSG striker's right ankle buckling in the tackle.

It provoked a furious reaction from the PSG squad, memories of Neymar's absences in previous campaigns perhaps fresh in their mind, and led to Mbappe's substitution.

That Perrin was eventually sent off following a VAR review - effectively ending Saint-Etienne's hopes of victory in the final - was scant consolation for the team that has reigned over France for years.

The Champions League is the prize they crave the most and, with their quarter-final kicking off in just 19 days' time, PSG may have to do once again do without one of their leading men.

And that's why the enduring image from what should have been a night of celebration was not of the trophy lift, but of Mbappe on crutches and in a lower-leg brace.