The Portugal winger, the Red Devils’ Mr Realiable this season, blasted his spot-kick wide following Gabriel Milito’s handball, to pass up the chance to give his side a precious away goal.
United were second best much thereafter, but restricted the Catalans to half chances only, despite their domination of possession.
Their best openings came in the second period with Xavi twice going close and Gianluca Zambrotta shooting just over. But Samuel Eto’o spurned their best opening when he fired into the sidenetting.
Substitute Thierry Henry twice tested Edwin van der Sar late on, while United’s best chance of the second period saw Michael Carrick fire into the sidenetting after he worked an opening.