Italian giants Juventus have been left with some work to do ahead of the second leg of the UEFA Champions League after losing 2-1 away to FC Porto on Wednesday night at the Estadio do Dragao.
Mehdi Taremi and Moussa Marega scored early in the first and second half respectively for Porto, before Federico Chiesa pulled one back for the visitors late on.
The visitors got off to a worst possible start as a defensive mishap involving Szcezesny and Bentacur allowed Taremi to close and get a block on the keeper's clearance, with the ball hitting the back of the net with two minutes on the clock.
The match was devoid of clear-cut chances for long in the opening half, with perhaps Adrien Rabiot's chance inside the six-yard box a few minutes to the break the only worthy mention.
Juventus' hopes of turning things around in the second period were hit after just 19 seconds of the restart as the hosts doubled their lead.
Marega found himself some space inside the box to get on the end of a pass from Wilson Manafa and sent the ball into the bottom right corner to make it 2-0.
Chiesa though showed great composure inside the box to fire in the equaliser for Juventus, handing them a lifeline ahead of the return leg in Turin.
Elsewhere, Erling Haaland scored a brace as Borussia Dortmund came from a goal down to beat Sevilla 3-2 in an entertaining clash.
The hosts took a seventh-minute lead as Suso found the back of the net following a pass from Fernando.
Haaland then took over, scoring twice and assisting the other as the Germans staged an unlikely comeback that ended Sevilla's nine-match winning streak.
First, the 20-year-old found Mahmoud Dahoud with a beautiful pass, and the player found the back of the net with a ferocious shot.
Haaland then put Dortmund 2-1 up following a neat pass from Jadon Sancho inside the box, before completing his brace with two minutes to the break.
Luuk de Jong slotted the ball into the bottom left corner late on to make the scores 3-2 and set a potentially exciting second leg.