Galaxy Coach Bruce Arena made adjustments to the lineup he used in a 1-0 loss to Houston on Saturday.
Midfielders Gyasi Zardes and Kenney Walker were part of the starting 11 — in Walker's second game of his
This paid off, with Keane opening up the scoring in the 24th minute. After handling a Zardes pass outside the 18-yard-box, Keane wiggled through three Dallas defenders before striking the ball into the net from distance, giving the Galaxy a 1-0 lead. The goal was the sixth of the season for Keane, the team's leading scorer.
Dallas captain Andrew Jacobson was injured during the goal-scoring play and had to be replaced by Adam Moffat.
The Galaxy threatened again in the 43rd minute when a perfectly timed Juninho through pass set up a Keane cross to Zardes, whose header was diverted by Zach Lloyd's arm. The referee decided the play was unintentional and did not rule a handball.
But Zardes would get his goal a minute later, when his header off a Juninho cross easily beat Dallas goalkeeper Raul Fernandez.
Galaxy defender Kofi Opare had to tread carefully in the second half after picking up a yellow card in the 37th minute for a sliding tackle on Dallas' Tesho Akindele beyond half-field.
The Galaxy continued the attack in the second half. Samuel's shot from inside the box went just right of Fernandez's goal in the 47th minute. In the 56th minute, Keane chested down a Stefan Ishizaki lob and one-timed it from the top of the box, narrowly missing the goal.
But the visitors pulled one back in the 65th minute. A giveaway by Walker near the 18-yard-box ended up at the feet of Dallas' Jair Benitez, who found a wide open Tesho Akindele inside the box for an easy goal.
Defensive miscues continued for the Galaxy, who lost Saturday's game by a goal that resulted from a miscommunication between goalkeeper Jaime Penedo and defender Dan Gargan.
In the sixth minute of Wednesday's match, Gargan and Penedo again put the Galaxy in a perilous situation. After disarming Dallas' Fabian Castillo inside the box, Gargan backpassed to Penedo, who picked the ball up with his hands, which constituted a handball and led to an indirect free kick from just outside the six-yard box. But no score came from the mistake.
Dallas continued to attack until the final minutes of the game. Je-Vaughn Watson's volley off a corner kick in the 88th minute caused the Galaxy a scare as it sailed over Penedo's crossbar, but the home team held on for the win.