Manchester United booked their place to play Wigan in the Carling Cup final after overcoming Blackburn.
Van Nistelrooy, Rooney and Saha were pivotal for United
Ruud Van Nistelrooy fired in a shot to put United ahead before Steven Reid equalised when he lashed home as both players pounced on defensive mistakes.
Zurab Khizanishvili was punished for handball to Blackburn's fury but Brad Friedel saved Van Nistelrooy's penalty.
A half-time tunnel fracas marred the tie before Louis Saha spooned in a volley for United's winner.
There was a slice of fortune about United's opener after Blackburn defender Michael Gray tried to intercept Wayne Rooney's pass but only succeeded in inadvertently diverting the ball to original target Van Nistelrooy.
The Dutchman took full advantage as his goal put United 2-1 ahead on aggregate and gave the home side an air of authority in their play, despite Ryan Giggs going off injured after 12 minutes.
Reid celebrates Blackburn's equaliser at Old Trafford but it proved in vain
Blackburn were getting little change out of the home defence until a mix-up at the back for United allowed Reid to level.
Kieran Richardson mistimed an acrobatic clearance on the 18-yard line and the ball ricocheted off Wes Brown into the path of Reid, who lashed in an angled shot from the right of the area.
Another error in the United defence saw keeper Edwin van der Sar come to his skipper Gary Neville's rescue by bravely racing out to clear his poor backpass before Morten Gamst Pedersen could take advantage.
Blackburn were then left fuming as Khizanishvili was penalised for handball in the area but will feel justice was done when Friedel saved Van Nistelrooy's spot-kick.
The first half ended in controversial fashion as players raced into the tunnel signalling some sort of fracas between the two sets of players.
Whatever happened only served to inspire United as they overpowered Blackburn after the interval.
Van Nistelrooy had a header superbly saved by Friedel, although the visiting keeper could do little when Saha spooned in a volley from Rooney's cross.
Blackburn's dismay with referee Graham Poll was furthered when they thought they should have had a penalty for a Rio Ferdinand handball before Friedel twice came to their rescue with excellent saves from Van Nistelrooy and Rooney.
But there were no other scares for United as they set up a Carling Cup final appearance on 26 February.
Man Utd: Van der Sar, Neville, Ferdinand, Brown, Evra (Silvestre 80), Rooney, Fletcher, Giggs (Smith 13), Richardson, Saha, van Nistelrooy (Vidic 86).
Subs Not Used: Howard, Rossi.
Booked: Smith, Richardson.
Goals: van Nistelrooy 8, Saha 51.
Blackburn: Friedel, Neill, Nelsen, Khizanishvili, Gray, Reid, Savage, Tugay (Peter 86), Pedersen, Kuqi (Emerton 76), Bentley.
Subs Not Used: Enckelman, Todd, Mokoena.
Goals: Reid 32.
Ref: G Poll (Hertfordshire).