Juventus' Fernando Llorente celebrates after scoring against Olympiakos' during their Champions League soccer match at Juventus stadium in Turin, November 4, 2014. [Photo/Agencies]

But Juventus, eliminated by Galatasaray in the group stage last season, were back to square one when Alberto Botia headed Olympiakos level three minutes later after goalkeeper Gianluigi Buffon carelessly gave away a corner.

"The ball went a bit longer than I thought so I decided to flick it on rather than risk catching it in those wet conditions," Buffon told Sky Sport Italia.

"The win was more than we deserved, as we conceded from two set pieces it would have been too harsh a punishment for us considering how many chances we created over the two matches."

Juventus, who swapped their usual 3-5-2 for a four-man defence and a diamond midfield, should have been ahead at halftime but missed a flurry of chances.

Alvaro Morata was sent clear but rolled the ball wide of Roberto's goal and Pogba then side-footed wide from the edge of the area after the ball deflected into his path.

N'Dinga's goal in the 61st minute, following another set piece, had them in real trouble but substitute Fernando Llorente, who replaced fellow Spaniard Morata, played a crucial part as Juve fought back.

Olympiakos led for four minutes before Llorente's header hit the foot of the post, struck Roberto's foot and bounced into the goal

One minute later, Llorente's cross found Pogba and, although Botia nearly managed to dispossess him, the ball fell to the Frenchman who slotted home from 18 metres.