Lee Barrett put the Leicester based side ahead in the 18th minute but Sphinx levelled through a penalty from Tom Thacker seven minutes later.
In the 27th minute, Dave Drennan fired Paul Charnley's side in front.
The second half saw four goals in a nine minute spell. Nick Brett equalised on 61 minutes. Four minutes later, pacy forward Jerome Murdock scored for Sphinx who, another four minutes later, went further ahead through a Craig Martin penalty.
4-2 to Sphinx became 4-3 in the 70th minute when Barrett hit his second of the match.
With fifteen minutes left, John Chapman drew Friar Lane level for a second time and in the 87th minute, Clinton Gunn hit the winner for the visitors.
Sphinx, who dropped to fifth in the Midland Alliance table after this defeat, are scheduled to travel to Oldbury United on Wednesday night for a league fixture.