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.
Gary Megson claimed his first win in charge of Bolton with the unlikely scalp of Manchester United, thanks to Nicolas Anelka's early strike.
United experienced their only previous league defeat this season back in August - against Manchester City - whereas that same month marked Bolton's only win in the Premier League - 3-0 against Reading.
Louis Saha has backed countryman Mikael Silvestre to make a full recovery from the knee injury that's expected to keep the defender sidelined until March.
Louis Saha was delighted to come through his first league start of the season against Blackburn Rovers unscathed after a long battle with a knee complaint.
Sir Alex Ferguson had planned to continue using the French striker in a bit-part role from the bench so as not to risk any further injury niggles.
Manchester United moved three points clear at the top of the Premier League thanks to Cristiano Ronaldo's double.
Prior to Saturday Blackburn had recorded seven wins in eight games and initially Rovers more than matched United, with strikers Roque Santa Cruz and Benni McCarthy looking lively.
Manchester United qualified for the Champions League knockout stage after a comfortable win against Dynamo Kiev.
United made five changes to the team that drew 2-2 at Arsenal, and it took a while for Sir Alex Ferguson's side to get into their stride.
Sir Alex Ferguson believes his young side are more than capable of going all the way in the Champions League this season after losing out at the semi-final stage last time out.
After opening their Group F campaign with three wins, the Reds can seal qualification for the knock-out stages with victory over Dynamo Kyiv on Wednesday evening.
Manchester United boss Sir Alex Ferguson has hinted he could rotate his squad more after having a strong bench at his disposal against Arsenal.
With the likes of Michael Carrick and Louis Saha available after injury, The Red Devils manager had five internationals at his disposal for the 2-2 draw at Emirates Stadium.
Manchester United defender Nemanja Vidic says he's become a better player working alongside his star teammates.
Vidic says training with players like Rooney, Anderson, Ronaldo, Nani, Tevez and Saha has helped him become a better player.
Manchester United boss Sir Alex Ferguson was delighted with the performance of Louis Saha off the bench for yesterday's 2-2 draw at Arsenal.
Saha helped create Cristiano Ronaldo's goal in the draw and Ferguson told MUTV: "I had the strongest bench that we've had all season, that's encouraging for us.