RSL dropped to 5-2 on the young Major League Soccer season and remained at 15 points. Sporting KC improved to an MLS-best 6-0 mark (18 points).
"Just a set piece," RSL goalkeeper Nick Rimando said of the lone goal. "They're so crucial in this game. Everybody knows that. A guy got free and headed home a great ball from Zusi. That's easy to chalk up on the chalkboard and take care of for next week and in the future. There's nothing to worry about. Everybody should keep their heads up high. It's early in the season."
The goal ended the RSL defense's scoreless streak at 268 minutes. Sporting KC, however, had its streak of not allowing a shot on goal end at 335 minutes. In the 91st minute, the first of four minutes of injury time, RSL's Nat Borchers tried to head in Kyle Beckerman's free kick, but goalkeeper Jimmy Nielsen was there for the easy save.
"It just wasn't our night tonight," Beckerman said. "All the boys battled. It was a little humid. We didn't expect the weather to be as muggy as it was this early in the season. Usually, it's in June or July."
Sporting KC tried to score off another Zusi corner kick in the 75th minute, but Rimando made a diving save on Kei Kamara's header.
"That was a big-time save," RSL coach Jason Kreis said. "That kept us in the game and really gave us a chance. Big credit to him for that play."
The RSL defense's scoreless streak came awfully close to ending in the 44th minute. C.J. Sapong's header into the net produced a lot of blue confetti on the field and cheers from the crowd. But the goal was waved off as Sapong was called for a foul for pushing RSL's Jamison Olave in the back.
RSL is back in action on April 21 at San Jose, which tied New York 2-2 on Saturday.
"It's a difficult place to play," Kreis said of Livestrong Sporting Park. "What a fantastic stadium. A fantastic crowd you have here. Our guys continued to fight. We had a chance until the dying end."