With David Beckham out of action again, Landon Donovan scored a goal and helped with three more to lead the Galaxy over FC Dallas 6-5 on Tuesday and earn Los Angeles a berth in the SuperLiga semi-finals.
Also advancing was Pachuca, which beat fellow Mexican team Chivas of Guadalajara 1-0.
Los Angeles finished the first round with two wins and one loss, despite playing without their new star midfielder in any of the three games. While the Galaxy will play in the semi-finals on Aug. 14, FC Dallas was eliminated from the tournament, which features four Major League Soccer (MLS) teams and four from Mexico.
Alan Gordon scored twice for Los Angeles.
Beckham, who has played only 16 minutes since joining the club on July 21, did not make the trip to Texas because of an ankle injury.
Beckham's availability for the club's next game on Sunday at Toronto FC, which would be his MLS debut, will not be determined until after practice today.
The game started and ended with a flurry of goals as the teams combined for six after the 78th minute, including four by FC Dallas as it almost erased a four-goal deficit.
The Galaxy scored four times in the first 18 minutes of the game with goals from Gordon in the third and 15th minutes, from Chris Klein in the 12th minute and Kevin Harmse in the 18th minute.
Carlos Pavon's goal in the 95th minute, which gave Los Angeles a 6-4 lead. Pavon fired a shot into the left corner of the net from about 12m away with an assist from Donovan.
Seconds later, Abe Thompson closed out the scoring with a header in the 96th minute.
Donovan gave the Galaxy a 5-3 lead after he raced past two FC Dallas defenders and placed a shot into the right corner of the net from 15m away for an unassisted score in the 84th minute. But Carlos Ruiz responded for FC Dallas with a goal in the 91st minute. FC Dallas had narrowed the lead to 4-3 after Arturo Alvarez scored his second goal of the game in the 82nd minute. Alvarez also scored on a header in the 43rd minute.
Rafael Marquez Lugo scored on a header in the 62nd minute off a pass from Christian Gimenez at Commerce City, Colorado, as Pachuca beat Guadalajara.