Los Angeles FC, coming off a year in which they won the Supporters' Shield as the top regular-season team in Major League Soccer, opened their 2020 season with a thud Tuesday.
Club Leon shut out LAFC 2-0 in Leon, Mexico, in the first leg of a CONCACAF Champions League opening-round series.
The teams will meet again for the second leg Feb. 27 in Los Angeles.
In the day's other opening-round match involving an MLS squad, Atlanta United played to a 1-1 draw against CD Motagua in San Pedro Sula, Honduras.
CD Motagua will look to pull off an upset in the second leg on Feb. 25 at Kennesaw, Ga.
Leon jumped on top in the 21st minute. Jean Meneses ran down a long cross-field ball to the left flank, then dribbled into the LAFC penalty area. He cut past one defender, who slipped, then slotted a hard shot inside the near post from 14 yards out.
The hosts doubled the lead in the 88th minute off an LAFC giveaway. Luis Montes picked up a giveaway just outside the Los Angeles penalty area, then fed an open Angel Mena, who calmly slotted home a 15-yard shot.
In Honduras, Motagua opened the scoring in the 33rd minute when Roberto Moreira volleyed home a right-footed shot from close to the penalty spot.
Atlanta United responded two minutes later when Josef Martinez completed a give-and-go play with Pity Martinez by rolling in a 12-yard shot off the left goalpost.
--Field Level Media