United 2 - 1 Sporting
Kuszczak and flew in at his near post. They could have added a second almost instantly, but Liedson's finish was ruled out for offside - a marginal decision at best.
As United struggled to maintain any attacking rhythm, Sporting were shooting on sight and Anderson Polga shocked Kuszczak with a snap-shot that the keeper held at the second attempt.
United boss Sir Alex Ferguson made a double substitution at half-time, sending on Tevez and Ryan Giggs for Nani and Darren Fletcher.
United did not have long to wait to restore equality, levelling on the hour when Ronaldo's shot was deflected in off a combination of Tevez and Sporting defender Marian Had.
Owen Hargreaves was introduced with 12 minutes left, and he almost scored with only his second touch, forcing another fine save out of the impressive Patricio from Anderson's pass.
But with time running out and United looking like they might need something from their trip to Roma to win their group, Ronaldo fired in a brilliant swerving free-kick to seal the win.
Man Utd: Kuszczak, O'Shea, Ferdinand, Vidic, Evra, Ronaldo, Carrick, Anderson, Fletcher (Tevez 46), Nani (Giggs 46), Saha (Hargreaves 79).
Subs Not Used: Van der Sar, Brown, Pique, Simpson.