LA Galaxy preserved their 100 per cent record on Tuesday, while Alonso Zamora led Tigres UANL's late rally.
LA Galaxy made it two wins from as many CONCACAF Champions League matches courtesy of a thumping 5-0 win at home to Comunicaciones.
Captain Robbie Keane and striker Alan Gordon both bagged braces, while midfielder Mika Vayrynen was also on target as the Galaxy continued their dominant start to Group D on Tuesday.
The Galaxy kicked off their continental campaign with a 5-1 humbling of Central a fortnight ago and the reigning MLS Cup champions produced another comprehensive display against the Guatemalan visitors at StubHub Center in Carson, California.
Former Liverpool captain Steven Gerrard watched from the stands but fans were treated to two goals inside the opening nine minutes, with Vayrynen and Gordon putting the home side into a commanding position.
Vayrynen broke the deadlock in the fifth minute via a volleyed effort before Gordon dispossessed goalkeeper Juan Paredes four minutes later.
Gordon netted his second of the game nine minutes after the break, when substitute Keane teed up the former inside the area.
Keane capped the resounding display with two quick-fire goals in the final three minutes of regulation time.
Copa Libertadores runners-up Tigres UANL rallied late as they overcame Isidro Metapan 2-1 in their Group B opener.
Tigres were staring at defeat on home soil in Mexico following Tony Rugamas' early opener, until Alonso Zamora struck in the 84th and 86th minutes.
Salvadoran outfit Isidro have lost their first two Champions League fixtures.
Meanwhile, Verdes and leaders Queretaro played out a goalless draw in Group C.