A horrible mistake by teenage substitute goalkeeper Dogan Alemdar gifted an equaliser to Breel Embolo as Monaco bounced back from their midweek Champions League elimination to draw 1-1 with Rennes in Ligue 1 on Sunday.
Alemdar hesitated inside his own six-yard box as he controlled a backpass from Joe Rodon, allowing the lively Swiss striker Embolo to steal in and score in the 73rd minute.
Embolo's goal cancelled out Gaetan Laborde's opener in the 59th minute for Rennes, as Monaco escaped with a draw despite playing the majority of the game at the Stade Louis II down to 10 men.
The principality side were looking to get back on track after their extra-time elimination at the hands of PSV Eindhoven in the Champions League third qualifying round, a setback which means they will instead go into this season's Europa League group stage.
Yet they were dealt a blow inside quarter of an hour when midfielder Youssouf Fofana was shown a straight red card for catching Rennes forward Martin Terrier on the shin with his studs right in front of the referee.
Despite that the home side were given the chance to take the lead from the penalty spot just after the half-hour mark when veteran Rennes goalkeeper Steve Mandanda rushed off his line to try to punch the ball away, only to catch Embolo on the head instead.
Mandanda redeemed himself by saving Axel Disasi's spot-kick, but was then taken off at half-time with Turkish youngster Alemdar taking his place.
Reigning champions Paris Saint-Germain host Montpellier later with Kylian Mbappe set to make his first appearance of the new season.
He missed the season-opening Champions Trophy win against Nantes a fortnight ago due to suspension, and then sat out the 5-0 victory at Clermont last weekend with a minor adductor injury.
Meanwhile, Sunday's scheduled match between Lorient and Lyon was called off because of damage caused to the Brittany side's pitch by the scorching, dry summer weather in France combined with a Celtic festival held on the surface last week.