Monaco were knocked out of the French League Cup semi-finals by En Avant Guingamp, losing 5-4 on penalty kicks after the game had ended in a 2-2 draw on Tuesday.
It was Leonardo Jardim’s first match back in charge of the club after he replaced his successor Thierry Henry.
Strugglers Monaco went 2-0 up in spite of being one man down early on, but finished the match exhausted as Guingamp forced a shootout.
They have now reached the final and will be up against either Racing Strasbourg or Girondins de Bordeaux in Lille on March 30.
Monaco’s William Vainqueur was sent off after 14 minutes for a dangerous tackle but the visitors stayed focused and went ahead four minutes later.
That was when Rony Lopes found the back of the net with an overhead kick.
Monaco, with Jardim on the bench for the first time since he replaced Henry last week, doubled their tally in the 28th minute.
Aleksandr Golovin scored with a powerful shot after being set up by Lopes.
Playing with 10 men eventually wore Monaco down and Guingamp pulled one back 16 seconds into the second half when Alexandre Mendy beat Danijel Subasic with a low shot.
Marcus Thuram levelled in the 55th minute with a 20-metre strike.
Guingamp coach Jocelyn Gourvennec replaced goalkeeper Kari-Johan Johnson with shootout specialist Marc-Aurele Caillard.
The move paid off as he saved two penalty kicks and saw Sofiane Diop’s effort crash against the bar.
Monaco, second from bottom in Ligue 1, must now focus on staying in the top flight having shown improvement under the returning Jardim.
He was sacked by Monaco last October before returning last week.