Buena Vista ran “her best race ever,” according to trainer Hiroyoshi Matsuda, as she walloped 17 rivals to win the $3.1 million Autumn Tenno Sho, or Emperor’s Cup, at Tokyo on Sunday. Sunday Racing Co.’s 4-year-old filly scored her fifth career Grade 1 victory as she rallied from midpack to defeat Pelusa by a decisive two lengths, getting the 1 1/4 miles on a firm turf course in a very quick 1:58.20 as the 6-5 favorite. “She is a superstar,” said rider Christophe Soumillon, who flew in from France especially for the assignment. “It was as if she had wings on her back.” For the record, the 3.90-1 second choice Earnestly was third, but Jaguar Mail, winner of the two-mile Spring Autumn Sho in May, showed nothing in finishing 15th. He was later being disqualified and placed last for interference. In victory, Buena Vista was paying her archrival Red Desire a big compliment. One of the favorites for the Breeders’ Cup Filly and Mare Turf, Red Desire had beaten Buena Vista by a nose in last year’s Grade 1 Shuka Sho after having finished a narrow second to her in both the Japanese 1000 Guineas and Japanese Oaks. In defeating males in a Grade 1 race for the first time in her career, Buena Vista, a daughter of Special Week who had been an unlucky second to Dar Re Mi in the Dubai Sheema Classic in March, was returning from a four-month layoff after finishing second in the Takarazuka Kinen to subsequent Prix de l’Arc de Triomphe runner-up Nakayama Festa. Buena Vista will now shoot for the two biggest races on the Japanese calendar, the 1 1/2-mile Japan Cup at Tokyo on Nov. 29 and the 1 9/16-mile Arima Kinen at Nakayama on Dec. 26. In both of those contests, she is expected to meet Nakayama Festa once again. In 15 lifetime starts, Buena Vista has never been out of the money, sporting a record of 8 victories, 4 seconds and 3 thirds for earnings of $10,275,185.