LOUISVILLE, Ky. - Rosie Napravnik made her first trip to the Churchill Downs winner’s circle Saturday night - first two trips actually - and now hopes for another first next Saturday when she rides Pants On Fire in the 137th Kentucky Derby. No female rider has ever won the Derby.  On Sunday morning, Napravnik got reacquainted with Pants On Fire - on whom she last sat on winning the Louisiana Derby on March 26 by guiding him through a half-mile workout that Daily Racing Form timed in 47.96 seconds over a sloppy main track. KENTUCKY DERBY NEWS: Track all the 3-year-olds on the Triple Crown trail  Napravnik said trainer Kelly Breen told her to go in just less than 48 seconds with a good gallop-out, which in fact, was the case.  “We were both real happy with the horse,’’ Napravnik said later. “Pants On Fire feels great so we’ll go from here and pray to the racing gods.’’  Said Breen: “The instructions were to see if you could break 48 [seconds], don’t go too, too fast - I don’t want 45 and change - but you may have to get after him to do that.  She said she just sat on him so that’s a good sign. And he came back as though he just galloped.’’  Napravnik hadn’t been on Pants On Fire since the Louisiana Derby and had never been on him before then. She wasn’t sure what to expect when she breezed him over a sloppy track, though Breen reminded her that Pants On Fire did win his maiden by seven lengths over a sloppy Delaware Park track last October.  “My first impression when I rode him in Louisiana was he was just super classy and he showed the same thing today,” Napravnik said. “He’s got a great demeanor. Without wasting any energy, he’s sharp enough; couldn’t ask for a better attitude in a horse.’’  Not only did Pants on Fire lift Napravnik’s spirits, but so did winning two races on Saturday’s opening-night card at Churchill including the first race of the meet. Though Napravnik won 110 races at Fair Ground - where she became the first female to win a riding title at that track - she won just 2 races from 66 mounts at Keeneland, with both of those wins coming on April 16.  “I hadn’t won a race in two weeks at Keeneland, thank God I still know how to ride, that’s great news,’’ Napravnik quipped. “I know Keeneland is the toughest meet in the world, but the last couple of days I was telling my fiancé Joe [Sharp] `I’m just sick of losing.’ ’’  Napravnik, 23, will be a major storyline this week as she is just the sixth female jockey to ride in the Derby and first since Rosemary Homeister Jr. finished 13th aboard Supah Blitz in 2003. Napravnik said she will relish the opportunity.  “Oh absolutely; with the media it gets a little crazy and very busy, but it’s all a very good thing,’’ she said. “I have Kelly Breen and [George and Lori Hall] to thank for putting me in the spotlight a little bit. I’ll just talk to whoever wants to talk to me. I’m very appreciative.’’