Teal Bunbury added his second goal in as many games for Kansas City (7-6-9), which has won two of its last three and climbed over .500 for the first time since its season-opening 3-2 win at Chivas USA. RSL (9-5-6) lost back-to-back games for the first time since April 2010.
Espinoza, whose hard tackle sparked a bench-clearing brawl in a 2-all preseason draw between the two clubs, was ejected for a hard tackle of RSL's Kyle Beckerman in the 57th minute.
He put Sporting up 1-0 in the 29th minute with his first goal since June 17, 2008 and only the second of his four-year career. Espinoza stole the ball from defender Collen Warner, dribbled into the area and put a hard left-footed shot past keeper Nick Rimando.
Bunbury made it 2-0 in the 34th, knocking home the rebound after Rimando saved Kei Kamara's header. Sporting keeper Jimmy Nielsen made three saves for his third shutout and first since a scoreless draw at Philadelphia on June 22.
