Goals from Anderson, Park Ji-Sung, Dimitar Berbatov and Danny Welbeck on Wednesday eased United to victory, with star forward Wayne Rooney creating two.
The visitors have now scored 18 and conceded two in their four matches across North America.
Sir Alex Ferguson’s side will conclude their pre-season tour in suburban Washington on Saturday against Barcelona, in a rematch of the Champions League final, which the Spanish side won 3-1.
The final score on Wednesday might have been a little misleading because David Beckham and his MLS All-Star teammates created a few good scoring opportunities. But they were nowhere near the level of the visitors in a match that drew a sellout crowd of 26,760 to Red Bull Arena.
The MLS’s showcase exhibition started with plenty of fanfare with parachutists floating into the arena, fireworks and a helicopter flyover.
Former Manchester United hero Beckham, now in his final year of a contract with MLS’s Los Angeles Galaxy, had an early chance to give the All Stars the lead but his 25-yard shot flew wide.
Rooney played a key role in United’s first goal, delivering a pass to Berbatov at the top of the area, taking a return pass and finding Anderson for a shot that beat MLS goalkeeper Faryd Mondragon.
Park doubled the score in the 45th minute, taking a pass from Patrice Evra at the top of the box, evading defender Sean Franklin and blasting a left-footed shot into the top right corner of the net.
In the 52nd, Rooney lofted a pass over the defense to Berbatov, who chipped the ball over rushing substitute goalkeeper Tally Hall only for it to hit the crossbar. Berbatov collected the rebound and fired into the net.
Welbeck completed the scoring in the 68th with a shot that deflected off defender Geoff Cameron.
Beckham gave the MLS fans in the crowd one last thrill when he bent a free kick around the wall in the 89th minute, but didn’t quite get it inside the post.