Monza took a surprising but deserved 1-0 home win over Juventus on Sunday, its first Serie A victory of the season, as the visitors struggled after being reduced to 10 men.
Juve key player Angel Di Maria’s return from injury was cut short after being sent off five minutes before the break after placing his elbow in Armando Izzo’s chest.
Juventus had half-chances in the first half but were struggling to create momentum, as Monza were effective in breaking down the play in midfield.
Dusan Vlahovic had several attempts on goal but none of them were difficult to catch for Monza goalkeeper Michele Di Gregorio.
Newly-promoted Monza smelled blood in the second half and pressured the opposition defence to make mistakes, while Allegri’s side tried to look for possibilities of a counter-attack.
Substitute Christian Gytkjaer became the hero when he slid in the winner from Patrick Ciurria’s cross in the 74th minute.
Moise Kean came close to equalising for Juventus in the 81st minute when his header went on target, but Di Gregorio was alert and held it firmly in his grip.
Allegri was not allowed on the bench for Juve’s first Serie A loss of the season, after being sent off last Sunday in the 2-2 home draw against Salernitana after protesting a disallowed VAR goal.
Juve fielded a depleted team as Arkadiusz Milik and Juan Cuadrado were suspended for the game, while Federico Chiesa, Kaio Jorge, Paul Pogba, Manuel Locatelli and Alex Sandro were all injured.
Monza next travel to Sampdoria on Oct. 2 after the international break while Juventus host Bologna on the same day.
Juventus remain eighth in the standings, but are now six points behind leaders Udinese after seven matches, while Monza moved up to 18th place with four points.