Danny Wilson scored early in the second half and the Colorado Rapids handed Los Angeles FC its second loss of the season, 1-0 in a game played in the rain on Friday night.
Colorado (5-9-4) extended its undefeated streak to seven matches. Los Angeles (11-2-4) had its undefeated run halted at eight games.
Wilson headed in a corner kick by Jack Price in the 49th minute. Colorado nearly made it 2-0 in the 84th, but Lee Nguyen cleared it off the line.
Los Angeles' Carlos Vela, the league leader with 16 goals, had his five-game scoring streak halted. LAFC hadn't played since June 1, due to the Gold Cup.
The match was stopped due to lightning in the area in the 52nd minute, and was delayed for nearly an hour. In the first minute of play after the delay, Colorado goalkeeper Tim Howard made a diving save of a shot from close range by Diego Rossi.