Lindsay Lohan On the Edge of Incredible -- She CRUSHES Stevie Nicks Live [VIDEO]

It's the first glimmer of pre-meltdown Lindsay Lohan we've seen in a long time -- she took the stage last night at some financier's NYC birthday to perform a classic Stevie Nicks song ... and she hit it out of the park.

Lindsay was at the Four Seasons -- where NY Republican Party Finance Committee chairman Matthew Mellon was celebrating his 50th birthday -- and she sang Stevie's "Edge of Seventeen" for the crowd.

Lindsay's had a love affair with "Edge of Seventeen" for years -- she's performed it live before and even featured a cover of the song on her 2005 album "A Little More Personal" ... a year after starring in "Mean Girls."