Manchester United have it all to do against CSKA Moscow on Wednesday night as they trail at half-time after Seydou Doumbia gave the hosts the lead.
Anthony Martial was guilty of giving the Russian side a penalty after his handball in the box, and although Roman Eremenko saw his effort saved by De Gea, Doumbia was on hand as he reacted first to slot home the opening goal of the game.
United travelled to Russia knowing that a positive result would have been a huge boost for their chances of progressing to the knockout stages of the tournament.
After losing to PSV in their opener, the Red Devils bounced back with a win over Wolfsburg at Old Trafford to leave all four teams in Group B level on three points apiece.
However, with a double-header against CSKA, Louis van Gaal’s side will be desperate to claw their way back into the encounter in order to have the advantage heading into the reverse fixture on November 3 in Manchester.
Their slow reactions from the spot-kick proved costly on this occasion as De Gea was left stranded, while the hosts look potent every time they attack as they look to make life more comfortable for themselves on the night.