Loan forward Lukaku restored parity for Inter deep into stoppage time at Allianz Stadium after Bremer was adjudged to have handled inside his area, before the goalscorer was dismissed for an altercation with Juan Cuadrado.

Cuadrado, who earlier thought he had won the game with his 83rd-minute strike, also saw red after the final whistle along with Inter captain Samir Handanovic following a clash between the pair.

The manic conclusion leaves the tie delicately poised as Inter return home on April 26 looking to reach the final and exact revenge for being on the wrong end of a Derby d'Italia double in Serie A this season.

Cup holder Inter was fortunate not to fall behind after four minutes as Handanovic produced an expert stop to deny a fizzing Angel Di Maria drive.

Mattia Perin provided an equally impressive save when unsighted to thwart a fierce Marcelo Brozovic attempt, as both sides went without first-half reward.

The contest remained bereft of clinical finishing after the break, Dusan Vlahovic heading over from Nicolo Fagioli's cross before Henrikh Mkhitaryan dragged just wide.

A low Cuadrado drive through a sea of bodies edged Juve in front, only for Bremer's handball to allow Inter a late leveller as Lukaku rolled his spot-kick into the bottom-left corner.

Chaos descended following that goal as Lukaku was dismissed for his celebrations in front of Cuadrado, who was then given his marching orders along with Handanovic after a full-time confrontation between the pair in the centre-circle.