Thomas Tuchel cannot explain Kylian Mbappe's drought in the Champions League but is confident the Paris Saint-Germain star can make a decisive impact against Manchester United.
Tuchel's men, who lost in last season's final to Bayern Munich, face a challenge to progress to the last 16 of this year's competition after a series of unconvincing performances in the group stage.
United, having won the reverse fixture in Paris, lead Group H with nine points, with PSG and RB Leipzig level on six points heading into the final two pool games.