David Ferreira, George John and Marvin Chavez did the damage for the Texan outfit who were far too good for David Beckham, Landon Donovan and co. to move into the final for the first time in their history.
Venue: Home Depot Center â€“ Carson, California
Yellow cards: LA - Dema Kovalenko 31â€™, David Beckham 74â€™, Chris Birchall 82â€™, Alex Cazumba 84â€™
FCD - Zach Lloyd 85â€™
FC Dallas keeper Kevin Hartman was keeping his team in the game early on with some top-shelf saves from an 8th minute Mike Magee shot before Juninho tested him 11 minutes later but he was equal to the task.
Two minutes later he was on hand to snuff out a David Beckham chance but as soon as Dallas took the ball down to their forward third they were successful.
GOAL David Ferreira received the ball on the edge of the area from Marvin Chavez, slipping away from two Galaxy defenders, before powering a near-unstoppable shot past Donovan Ricketts to give his side an invaluable lead.
Minutes later, it was Hartman again who came up with the goods when Landon Donovan was released on the left-hand side of the box but his strike was flicked away by the diving left hand of the Dallas gloveman who was in stellar form.
GOAL Less than ten minutes into the second half, Dallas went two ahead when Brek Shea was released down the left before cutting back for an unmarked George John who knocked it in from the back post for his first of the season.
The Galaxy chased hard and were almost immediately back in touch when Donovan tried his luck with a speculative left-foot volley which was only inches over the crossbar as the players became more and more desperate in their advances forward.
Beckham was doing what he could to bring his teammate into the contest but things only got worse for the Galaxy when Dallas scored a third.
GOAL This time Ferreira turned provider when he played a smart through ball for Chavez who finished neatly to make it 3-0 with just over 15 minutes remaining.
The Texan outfit were able to maintain control of the final quarter of an hour of the contest and there were jubilant celebrations as they took out the Western Conference title, qualifying for the MLS Cup final where they will Colorado Rapids at BMO Field in Toronto on Sunday.
Donovan Ricketts (gk), Eddie Lewis (Kirovski 82â€™), Omar Gonzalez, AJ DeLaGarza, Sean Franklin, Landon Donovan, Juninho, Dema Kovalenko (Birchall 66â€™), David Beckham, Edson Buddle, Mike Magee (Cazumba 55â€™)
Subs - Alex Cazumba (55â€™), Chris Birchall (66â€™), Jovan Kirovski (82â€™)
Kevin Hartman (gk), Jackson Goncalves, George John, Ugo Ihemelu, Jair Benitez, Marvin Chavez (Lloyd 74â€™), David Ferreira, Dax McCarty (Alexander 87â€™), Daniel Hernandez, Brek Shea, Atiba Harris
Subs - Zach Lloyd (74â€™), Eric Alexander (87â€™)