Gerso Fernandes and Ilie Sanchez scored goals in each half and Sporting Kansas City became the first team to beat LAFC at home in Banc of California Stadium with a 2-0 MLS Western Conference victory on Saturday night.
Sporting KC goalkeeper Tim Melia had five saves while recording his ninth clean sheet and second in consecutive matches.
Sporting KC took an early 1-0 lead. After LAFC's Diego Rossi lost possession on Sporting KC's half of the field, Diego Rubio maneuvered through traffic and fed Fernandes for a left-footed shot that was out of the reach of goalkeeper Luis Lopez.
The score, in the 17th minute, was the third MLS goal for Fernandes, and his second in the club's past three MLS matches. He also scored at home against FC Dallas on July 28.
Sanchez added a goal from the penalty spot in the 66th minute after Felipe Gutierrez was fouled in front of the goal by LAFC's Dejan Jakovic. The penalty, for dangerous play, was confirmed via the video assistant referee (VAR) system.
LAFC had five victories and five ties at its new stadium in MLS play before falling on Saturday, and the club was also unbeaten in 14 matches at home across all competitions.
In a battle of teams tied for third place. Sporting KC moved into sole possession of second place. LAFC is now tied for fourth with the Los Angeles Galaxy.
LAFC appeared to battle fatigue throughout after playing 120 minutes against the Houston Dynamo on Wednesday in the U.S. Open Cup semifinals. Houston advanced after eight rounds of penalty kicks.
Sporting KC was rarely threatened on defense Saturday until late in the match. LAFC's Andre Horta hit the right post on a chip shot in the 79th minute. Christian Ramirez, in his first match with LAFC after being traded from Minnesota, hit the right post in the 85th minute.
After Wednesday's long match, All-Star Carlos Vela did not enter until the 58th minute. LAFC's top scorer Adama Diomande was out with a hamstring injury.
Sporting KC won its second consecutive MLS match following a five-match winless streak. With the victory at Houston on Aug. 4, Sporting KC has won consecutive matches on the road for the just the second time since the start of the 2015 season.