Barcelona goalkeeper Marc-Andre Ter Stegen's double save from a penalty helped earn a 0-0 draw in their Champions League opener at Borussia Dortmund.
Just before the hour mark, the German produced a stunning stop at full stretch to deny countryman Marco Reus and then got up to calmly collect the bouncing rebound.
Replays, though, showed Ter Stegen had been off his line when the spot-kick was taken, but there was no video assistant referee review.
Barcelona brought Lionel Messi on for the closing stages, to replace 16-year-old Ansu Fati, for a first appearance of the new season. However, the Argentina playmaker was not able to help conjure a goal, seeing a stoppage-time effort blocked.
Dortmund had earlier hit the crossbar through substitute Julian Brandt and but for some wayward finishing, as well as the heroics of Ter Stegen, could count themselves unfortunate to have to share the points from the Group F fixture.
Ajax Amsterdam gave a powerful reminder of their Champions League potential with a resounding 3-0 win over Lille in Amsterdam.
Last season's surprise package look hellbent on a repeat of their heroics, which got them all the way from the preliminary rounds to the semi-finals, and goals from Quincy Promes, Edson Alvarez and Nicolas Tagliafico ensured an emphatic start to Group H.
Substitute Nicolo Barella scored a stoppage-time equaliser on his Champions League debut to rescue a dramatic 1-1 draw for Inter Milan at home to Slavia Prague.