Omar Bravo's 90th-minute penalty kick 2 draw with the Los Angeles Galaxy at Livestrong Sporting Park on Monday.
Sean Franklin put the Galaxy ahead midway through the first half, but his opener was canceled out by Julio Cesar in the 72nd minute.
L.A. regained the lead two minutes later with Franklin's second goal of the contest, but Frankie Hejduk handled the ball inside his own penalty area in the 90th minute, allowing Bravo to fire home the equalizer.
The result moves the Galaxy four points clear at the top of the Western Conference table, while Sporting closes to within three points of the Columbus Crew at the top of the East standings.
Graham Zusi went close with a 25-yard effort in the 15th minute, but the only shot on target for either team in the first half came in the 25th as Omar Gonzalez nodded the ball into the box for Franklin to volley home from 12 yards.
It wasn't until the final 20 minutes that the match really came to life and the home side leveled the game from a corner kick as Cesar was on hand at the back post to volley the ball past goalkeeper Josh Saunders.
But it took the Galaxy less than two minutes to restore its lead as David Beckham collected a loose ball at the edge of the area and slid it to the right for Franklin, who was left open inside the box and rolled the ball underneath goalkeeper Jimmy Nielsen.
Aurelien Collin thought he equalized for Sporting with a header in the 84th, only for the goal to be called back for offsides. However, Cesar's cross into the area in the 90th minute skipped off Hejduk's arm and Bravo buried the spot kick to claim a point.