It's been a struggle for the Union to produce positive results this season, a situation which has increased the pressure on manager John Hackworth, but after a scoreless first half the Union struck first in the 49th minute.
Maidana did well to get around his mark and gallop the end line. His strike from a tight angle was parried by Sporting goalkeeper Eric Kronberg, but the rebound came straight to Danny Cruz, who finished it on the slide and all the Union players surrounded their manager in a show of unity and support.
Kansas City responded to going down a goal by inserting top goal scorer Dominic Dwyer and the move paid dividends in the 80th minute as he ran onto a layoff from Paulo Nagamura and ripped it into the top right corner.
But less than a minute later the Union took the lead again as Andrew Wenger found a wide-open Maidana in the box and the Argentine finished with his right foot.
The Union faced more adversity in the final minutes as substitute Corben Bone was shown a straight red card for a reckless challenge just moments after his introduction.
But Philadelphia held firm to claim a massive three points and move into seventh place in the East with 11 points. Despite the defeat, Sporting remains in first place in the East on 17 points.