The Union staged a remarkable second-half comeback, scoring three times to force a 4-4 draw after the Revs led 4-1 shortly after the half-hour mark.
Rookie AJ Soares opened his MLS account and the scoring on the night for New England at Phillieâ€™s PPL Park with a ninth minute unmarked header from Chris Tierneyâ€™s pinpoint free-kick before Rajko Lekic converted from the penalty spot in the 21st minute.
Revsâ€™ new signing Monsef Zerka marked his MLS debut with a simple header at the back post in the 26th minute from another dangerous Tierney ball to make it 3-0 before the Union finally got into the match two minutes later thanks to a brilliant reply from Roger Torres who struck with his left from the edge of the area, giving Matt Reis no chance in Revs goal.
Just as it the Union seemed to be getting back on track, New England made it 4-1 in the 33rd minute when Benny Feilhaber hammered home from outside the area.
Union coach Peter Nowak must have had some choice words at half-time because his side came out firing in the second half and within ten minutes had a second goal through the returning Freddy Adu who netted his first MLS goal since 2007 with a neat finish from Danny Mwangaâ€™s pass to make it 4-2.
With just over ten minutes remaining, Sebastian Le Toux cut the lead to one with a successful spot-kick before the Frenchman completed the comeback in injury time with a blistering volley from 12 yards.
The draw allowed Philadelphia to move to third on the Eastern Conference table whilst the Revs remained second bottom as their winless streak ran to seven matches.
Philadelphia Union: 4 (Roger Torres 28â€™, Freddy Adu 54â€™, Sebastian Le Toux (p) 80â€™/90+1â€™)
New England Revolution: 4 (AJ Soares 9â€™, Rajko Lekic (p) 21â€™, Monsef Zerka 26â€™, Benny Feilhaber 33â€™)
PPL Park, Chester, PA â€“ 16,148