Manchester United’s Director of Football Jason Wilcox described Mainoo’s contract extension as a major boost for the club.
Young’s football journey began at Watford in 2003.
Reigning UEFA Champions League champions Paris Saint-Germain edged Bundesliga champions Bayern Munich in a nine-goal thriller on Tuesday night.
The Blues’ poor run also included defeats to Paris Saint-Germain in the Champions League.
Brighton thrash Chelsea 3-0 at the Amex Stadium to deal a blow to the Blues’ Champions League qualification hopes.
Inter Milan beat Como to advance to the Coppa Italia semi-finals.
The Los Blancos opened the scoring in the 30th minute with a deflected strike from Kylian Mbappé, netting his 24th goal of the season.
Wolves spent over 30 consecutive matches at the bottom of the league standings, conceding more than 60 goals while scoring just 24.
The extra 30 minutes failed to produce more goals, pushing the game to penalties.
Harry Maguire and Lisandro Martinez both missed the game due to suspension.
