Man Utd 3-0 Portsmouth
Manchester United marked Sir Alex Ferguson's 20 years as manager by cruising to victory - and extending their Premiership lead to three points.
Louis Saha opened the scoring from the penalty spot after Portsmouth's Dejan Stefanovic tripped Wayne Rooney.
Cristiano Ronaldo then scored a superb free-kick, while David James denied Gary Neville three times in the match.
Niko Kranjcar missed a great chance for Pompey before Nemanja Vidic headed his first goal at Old Trafford.
BBCManchester United manager Sir Alex Ferguson:
"We have had a fantastic start (to the season). Historically, we don't always have good starts.
"We have made one this year and we need to take advantage of it.
"I have to be honest and say there is a confidence about the place that suggests we are now in a position to pull out all the stops and go for it." Portsmouth assistant manager Joe Jordan:
"I am sure they are capable of giving the reigning champions a real run for their money.
"They still have to prove they are capable of maintaining that form throughout the season.
"But at this moment in time, there is no question they are flying. They are playing with great confidence."
Man Utd: Van der Sar, Neville, Ferdinand, Vidic, Evra, Ronaldo (Fletcher 75), Carrick (Silvestre 71), Scholes, Giggs, Rooney (O'Shea 75), Saha.
Subs Not Used: Kuszczak, Brown.
Goals: Saha 3 pen, Ronaldo 10, Vidic 66.
Portsmouth: James, Pamarot, O'Brien, Stefanovic, Taylor, Pedro Mendes, Davis, Kranjcar (Hughes 84), Fernandes (Cole 46), O'Neil, Mwaruwari (LuaLua 66).
Subs Not Used: Kiely, Kanu.