Atiba Harris threw a spanner in the works when he netted for Dallas in the 22nd minute but Galaxy stars Landon Donovan and Beckham combined in the 33rd minute to level the scores.
Donovan won the ball on the byline before teeing up Beckham who finished with a low, powerful shot from outside the area, sending the home crowd into a frenzy. It was Donovan’s 16th assist and Beckham’s second goal of the season.
Straight after the break, Brazilian midfielder Juninho put the Galaxy ahead when he hit a perfect volley from the top of the area after a deflection from a Dallas defender fell to him and the goal was enough to give Los Angeles the win which allowed them to finish the regular season three points ahead of nearest rivals Real Salt Lake and record a franchise record of 18 wins.
It was the third Supporter’s Shield won by the Galaxy, following on from their 1998 and 2002 triumphs, and going one better than their second-place finish last season.
Venue: Home Depot Center – Carson, California