DC First: Batgirl & The Joker (2002) #1

One-shot. WRITTEN BY STEVEN GRANT; ART BY BILL SIENKIEWICZ AND TERRY MOORE; COVER BY KEVIN NOWLAN.

When Oracle recounts her first encounter with the Joker as the original Batgirl, the current Batgirl gets it in her mind to challenge the Clown Prince of Crime to a duel.

(Note: reference picture, not an actual scan)