Sporting Clube de Portugal were held to a 0-0 draw at home to FC Basel 1893 in their Group G opener.
Though it was a fifth meeting in less than five years between the sides, it did not follow the pattern of the recent past. Sporting had won all four previous meetings without conceding a goal and, although they once again kept a clean sheet, Ricardo Sá Pinto's side were made to work particularly hard after Xandão's dismissal.
Languishing in the unfamiliar surroundings of fifth from bottom in the Portuguese Liga, Sporting were equally slow to find their feet here. Elías, Ricky van Wolfswinkel and Cédric all failed to work Yann Sommer early on, but it was Basel's Aleksandar Dragovic who was most guilty of profligacy. Ghosting in unnoticed at the back post, he met Alexander Frei's free-kick with precision timing but headed over.
Van Wolfswinkel was in typically sparky mood and almost put Sporting in front just before the break when he latched onto Andre Carrillo's perfectly weighted pass and unleashed a fizzing shot. Sommer, though, was up to the task.
If a goalless opening period had forced Sá Pinto to ponder Plan B, Xandão's 50th-minute dismissal triggered a total rethink. Indeed, it could have been a different script altogether had Marcelo Díaz's thunderous drive skirted the frame of Rui Patrício's goal rather than skim off the crossbar.
Though Van Wolfswinkel cut an increasingly isolated figure, he did fashion a half-chance with 15 minutes left when he controlled adroitly with his chest only to shoot tamely at Sommer.