Stevie Nicks paid tribute to pal Tom Petty at a concert in Los Angeles last night (20May07) when she spotted the rocker in the audience. The Fleetwood MAC singer ripped into a version of Petty's I Need To Know, which she performed with Petty and his band the Heartbreakers on their U.S. tour last year (06). Failing to persuade her Stop Draggin' My Heart Around duet partner to join her onstage for the Greek Theatre gig, Nicks cooed about touring with Petty, calling her 2006 trek with him "the best time I've ever had."