The first thing you have to understand about Isidro Metapan and Puetro Rico Islanders is that they're both younger than the Galaxy. If you haven't googled them already, Isidro Metapan were formed in the year 2000 by the merging of the CD Isidro Menedez and, wait for it, Metapan FC. The two clubs both trace their history back much longer than that, but neither were a power in the first division.
Puerto Rico Islanders were formed in 2003, and played one year in the A-League before the A-League became the USL First Division with future MLS franchises Portland Timbers, Seattle Sounders, Vancouver Whitecaps, and Montreal Impact. Puerto Rico joined the new NASL after the USL First Division folded.
Now formidable in El Salvador, Isidro Metapan won the 2011 El Salvadorian Primera Division Apertura, lost 2-1 in the Clasura final to Aguila. The Salvadorian teams haven't performed too well in Champions League this year, with Aguila having a -9 goal differential and Isidro giving up five goals to the Galaxy.
Puerto Rico lost 3-1 at Metapan to kick off play in Group 5. Puerto Rico finished in third place in the 2012 Caribbean Club Championship. Winners Caledonia have managed a draw against Marathon and now face the Seattle Sounders. Second place Connection managed a draw against Xelaju of Guatemala who defeated CD Guadelajara in their other CCL match.
Should the Galaxy defeat Puerto Rico tomorrow, six points will put them at the top of the group. September will see Puerto Rico host the Galaxy and then Metapan, so the group could be decided by the end of the month. If not, the group has one last match in October when the Galaxy visit El Salvador.