Marcel Sabitzer scored twice inside the opening 25 minutes of action, as Erik ten Hag's men went in at the break in a seemingly commanding position.
But the visitors were given a lifeline in the 85th minute when former Manchester City winger Jesus Navas pulled the ball back on the right and it deflected off Tyrell Malacia and then David De Gea to make the score 2-1.
Another freak goal, when Youssef En-Nesyri's header struck Harry Maguire and bounced beyond our no.1, levelled the score at the halfway point in the tie.
Full report to follow.