In the style in which they demolished Bolton at the Reebok in the opening stages of last week's game, the reds gave Portsmouth a taste of the same medicine.
United's first half performance was again out of the top draw and with his team playing this type of football, Ferguson must be tempted to go on forever.
With Wayne Rooney irresistible and Luis Saha leading Pompey a merry dance, United thrived even more as Christiano Ronaldo and Gary Neville were given the freedom of the park down the right.
United took the lead with their first serious attack in the second minute.
Neville's quickly taken throw on the right released Rooney into the Pompey box and he was brought down by Dejan Stefanovic with a little assistance from Mathew Taylor. Referee Mike Dean pointed to the spot and Saha stepped up to fire his left foot penalty beyond the diving David James and into the top right corner of the net.
Portsmouth's hope of a point with a five man midfield lay in tatters after only nine minutes.
Andy O'Brien brought down Saha twenty five yards out and Ronaldo stepped up to lash his vicious right foot free kick into the top left corner of the net.
But for the magnificent James, it could have been a cricket score before the break.
Paul Scholes, again in imperious form for the Red's in central midfield, found Neville free on the right. The England right back beat two defenders as he cut across the edge of the box before firing in a shot which James saved with a combination of arms and legs.
An even better move in the 23rd minute saw Scholes find Rooney with another perfect pass. Rooney steered an equally impressive ball to Neville, again free on the right edge of the Pompey box and his vicious shot was finally saved by the diving James.
The Portsmouth goalkeeper tipped away a Rio Ferdinand header seconds later and O'Brien cleared a Scholes shot from almost off his line after James had beaten away a Rooney effort.
Pompey's best chance of the half came in the 43rd minute when United goalkeeper Van Der Sar did well to beat away a thundering 25 yard drive from Taylor.
United continued to press forward after the interval, although Pompey brought on former Red's hero Andy Cole for the ineffective Manuel Fernandes to give Benjani much needed support up front.
James produced another excellent save to deny Vidic from point blank range after Saha had flicked on Ronaldo's corner.
Rooney's superb pass put in Neville again after 64 minutes, but as he tried to round James and score the Pompey goalkeeper just got a touch to the ball.
But the Red's only had a minute to wait for their third goal.
Neville was the provider with a right wing cross to the near post and Vidic coasted in to score with a header from ten yards.
Pompey almost scored a consolation goal deep into injury time when a miss-understanding between Ferdinand and Van Der Sar presented Taylor with an open goal, but he shot wide from ten yards.