Despite starting an unusually large number of regulars (there were still six changes to the lineup that faced Real Salt Lake Saturday), it took Landon Donovan coming on as a substitute for the Galaxy to unlock the rear guard action of their Costa Rican opponents Tuesday in Carson in a CONCACAF Champions League opener the home team wanted to win by two clear goals.

MLS beat writer Phil Collin was one of 9,474 on hand for the game and filed this report.

Notable: Defender Kofi Opare made his debut and midfielder Robbie Rogers will undergo a scan today to determine the severity of a hamstring issue that forced him from the game prematurely.

Quotable: “It wasn’t a convincing performance but we played well enough to certainly win the game,” said striker Robbie Keane. “It’s always nice to get a couple of goals because goal difference is very important in this [competition.]”

Here’s the significance of the win in the tournament, according to the Galaxy website:

• The Galaxy are now tied with Cartagines for the top spot in Group 8. Both teams have three points with the Galaxy standing at 1-0-0 while Cartagines are 1-1-0. Isidro Metapan are in third place with an 0-1-0 record and no points.

• The Galaxy also have the best goal difference in the group at +2 while Cartagines are even and Metapan are -2.