Saturday's $3 million Cox Plate in Australia will be the most important race in the career of the celebrated super mare, Sunline, her jockey, Greg Childs, says.Sunline, a two-time winner of the Cox Plate, will have her 48th and final race at Moonee Valley. Childs says she can exit with "a blaze of glory" while equaling the record of Kingston Town, who won Australasia's weight-for-age championship contest three times. "This is Sunline's most important race because there is no coming back to have another shot," Childs told the AAP Racing and Sports."She's so close to equalling Kingston Town's record you can almost touch it," he said. "It's not the end of the world if she gets beaten; she already has two Cox Plates under her belt, but now is her chance to win three."Sunline's last start, when she was defeated by Lonhro when just short of leading all the way to the wire in the Yalumba Stakes, in a race run in near record time, has her fit for the Cox Plate, Childs said."She's going out and I just hope that we go out in a blaze of glory," he added.Sunline has won 32 of her 47 starts and been placed in 12 others, amassing earnings of more than $11 million. She is a three-time Australian Racehorse of the Year.Childs has ridden her in most of her races.Besides Lonhro, other Cox Plate hopefuls are Bel Esprit, Ustinov, Assertive Lad, Macedon Lady, Bomber Bill, Falvelon, Century Kid, Shot of Thunder, Sky Heights, Excellerator and Phoenix Park. Caulfield Cup winner Northerly and second place Fields of Omagh are also set to clash again.