Favourite Royal Delta ran out of steam to be thwarted in her bid to win the $2 million Breeders' Cup Distaff for a third consecutive time as Beholder stormed to a commanding victory at Santa Anita Park.
With veteran Hall of Fame jockey Gary Stevens on board, Beholder took control of the day's feature race by the final turn before charging down the home straight to triumph by four and one-quarter lengths.
Close Hatches finished second with Authenticity third while Royal Delta, a 7-5 favourite heading into the starting gate, ended up a disappointing fourth out of six runners in glorious late afternoon sunshine.
Royal Delta had been bidding to become only the second horse to win a Breeders' Cup race for a third successive time, emulating Goldikova who won the Mile in 2008, 2009 and 2010.
"This is the best race she's ever run," a beaming Stevens, 50, told reporters about Beholder after winning the ninth Breeders' Cup race of his career, but his first since 2000.
"I was hoping that Authenticity would carry the lead a little farther but (Beholder) moved up nice, went by her easy and then really opened up.
"She was a little fractious going into the gate and a little anxious. I was afraid she might over-break but she settled and broke beautiful," added Stevens, who retired from racing in late 2005 before making a comeback this year.
The Richard Mandella-trained Beholder, the top three-year-old filly on the West Coast, had previously won four times this season, including grade I victories in the Santa Anita Oaks and the Zenyatta Stakes on Sept. 28.
Royal Delta, piloted by Hall of Fame jockey Mike Smith, held the early lead then slipped back into second behind Authenticity by the first turn before fading badly with five furlongs to go.
"She didn't have it today," said Smith, who had extended his record number of Breeders' Cup career wins to 19 earlier in the day. "No spark, man. Early on, I knew it. She usually takes the race to somebody, but not today.
"I thought when Beholder come up to her, she would pick it up, but she didn't. I asked and I asked and nothing. I'm kind of dumbfounded."
Royal Delta won the Distaff (previously the Ladies' Classic) in 2011 with an explosive finish at Churchill Downs in Kentucky, then successfully defended her title at Santa Anita last year with another command performance.
On Friday, however, she was unable to maintain the pace as Beholder, Authenticity and Close Hatches dueled for the lead over the latter half of the race.
"He (Mike Smith) tried to get her to go on a little more on the first turn and she didn't," said Hall of Fame trainer Bill Mott, who had prepared both Royal Delta and Close Hatches for the Distaff.
"She's had three hard campaigns. I've been very blessed to have a lot of good horses and it's difficult to have more than two good campaigns with any horse.
"I think Gary (Stevens) had the plan to wait and make a little run. She did and his filly ran a tremendous race."