United lifted the Community Shield for a record-extending 13th time, after overcoming Portsmouth in a penalty shootout at Wembley Stadium.
The Reds dominated for long spells against Harry Redknapp's side, but found themselves frustrated by another superb display from Pompey goalkeeper David James, who made fine second-half saves from Darren Fletcher and Carlos Tevez.
The England international was unable to extend his heroics into the shootout, however, as Tevez, Ryan Giggs and Michael Carrick all found the net, while Pompey missed three of their four kicks.
In normal time, the only clear opening of the first 45 minutes fell to Fletcher after Nani superbly robbed Glenn Johnson and crossed into the box. In sliding to reach the ball, Fletcher ended up stubbing his effort into the ground and effectively blocking his own shot.
United's dominance continued in the second period, with James called upon to superbly tip Fletcher's chip onto the crossbar and then clutch the rebound gratefully as Tevez managed to head an effort goalwards.
James made another stunning fingertip save to turn a Tevez effort wide of his right-hand post shortly afterwards, before Jermain Defoe burst through on goal in a rare Pompey attack, only to be denied by fine tracking back from Vidic.
With 15 minutes remaining, United should have been handed the chance to win the game from the spot when Hermann Hreidarsson inexplicably held onto Tevez's leg inside the area, but referee Peter Walton saw no wrong.
Although John Utaka notched Pompey's first shot on target - after 77 minutes - the pressure was still all United's. Substitute Fraizer Campbell fashioned space for himself but fired over the bar, and the Reds kept pressing until the very end.
Penalties were required though and, having triumphed against Chelsea in last year's Shield and the Champions League final, United had every cause to be confident. Serial spot-kick hero Edwin van der Sar was only required to make one save - from Arnold Mvuemba - as Lassana Diarra and Glenn Johnson both blazed their kicks over.
Johnson's effort sealed a 13th outright Community Shield triumph for the Reds - as well as five shared Shields - and ensured a silver-lined start to the 2008/09 season.
Manchester United: Van der Sar; Neville (Brown 67), Ferdinand, Vidic, Evra; Fletcher, O'Shea (Carrick 67), Scholes, Nani (Campbell 79); Giggs, Tevez.
Subs not used: Kuszczak, J Evans, Possebon, R da Silva.
Booked: Vidic, Neville
Portsmouth: James; Johnson, Campbell, Distin, Hreidarsson (Lauren 80); Diop, Mendes (Mvuemba 76), Diarra, Kranjcar (Utaka 60); Crouch, Defoe.
Subs not used: Ashdown, Sahar, Cranie, Traore.
Round up by Steve Bartram