Barcelona were held to a 0-0 draw by Olympiakos as they failed to score in a Champions League group stage game for the first time in five years.
Luis Suarez hit the crossbar as Barcelona sought to secure the win that would qualify them for the knock-out stage with two games remaining.
The striker then unselfishly tried to tee up Lionel Messi instead of going for goal himself after an hour.
Barca top Group D by three points after Juventus drew 1-1 with Sporting Lisbon.
Ernesto Valverde, who was making a return to his former club, has guided his Barca side to 10 points from four games.
Only a point is required from their last two games against Juventus and Sporting to guarantee a place in the last 16.
Juventus, who have two wins, a draw and one defeat, are still three points clear of Sporting in third.
Gonzalo Higuaín equalised with 11 minutes remaining after Bruno César had given Sporting a half-time lead.
The late equaliser ensures Juve remain in a strong position to progress through to the knock-out stage.