Jockey Mike Smith celebrates after guiding Zenyatta to victory
Star American filly Zenyatta put in a sensational performance to win the Breeders' Cup Classic, the richest race on the two-day card at Santa Anita.
It was her 14th career win and came against her male rivals.
Earlier, Conduit, from the Sir Michael Stoute stable, put in a strong finish to claim back-to-back wins in the Breeders' Cup Turf under Ryan Moore.
There were also wins for French challenger Goldikova and the John Gosden-trained Pounced.
Zenyatta made a poor start but fought off Gio Ponti in the straight to win by a length, becoming the first female to win the Classic in its 26-year history.
Rounding the final turn, the five-year-old mare still had a lot of ground to make up but, under US Hall of Fame jockey Mike Smith, made a bold inside move to claim victory.
"She's sent from heaven," said Smith. "She's incredible. I still didn't hit all gears. She's horse of the decade by far. She should go down as one of the greatest horses of all time."
Owners Jerry and Ann Moss said Zenyatta, named after the 1980 album "Zenyatta Mondata" by The Police, will probably go to the breeding shed next year.
Conduit had to work harder than when winning 12 months ago after overhauling Presious Passion close to the line.
Presious Passion set his usual frantic early pace but came right back to the field turning into the straight before kicking on again in the straight.
But Conduit kept up his charge to win by while Dar Re Mi claimed third with Spanish Moon, stablemate of the winner, fourth.
Champion jockey Moore said: "I didn't want to go wide and then get beat but luckily the opportunity was there for him.
"He wasn't fast away and I was in behind Red Rocks and Telling which are not the sort of horses you want to be tracking round.
Conduit won the King George VI and Queen Elizabeth Stakes at Ascot
"I got forward in the straight and I used a bit of petrol but to be fair to the horse, he was very game.
"He's been a great horse for me and sort of a once in a lifetime horse. I believe he's going over to Japan now and we'll see how he gets on there."
Stoute added: "It's always a big day and these are the world championships. This is a very important race and it's great to see him go and win it twice in a row.
"We're thrilled with him and we're also pleased with the fourth horse, Spanish Moon."
Goldikova won the Turf Mile for the second year in a row, emulating the feat of Miesque, who was ridden by her trainer Freddie Head.
Jockey Olivier Peslier bided his time at the back of the field and had to weave through runners in the straight but once the four-year-old got into gear she looked impressive.
Head, who said that his charge could go for a third win next year, was full of praise for the filly.
"She is very easy to train and does everything herself. She always gives her best, never has a problem and never puts a foot wrong so she is quite special," said Head.
"I don't have the words to express how I feel. To ride a horse like Miesque and now train a horse like Goldikova is something you can only dream of.
Frankie Dettori moved level with Chris McCarron as the third most successful jockey in the 26-year history of the meeting when Pounced got the better of Bridgetown in a thrilling finish to the Juvenile Turf.
Frankie Dettori performs his traditional dismount after the win for Pounced
Dettori's mount, who went off as favourite, travelled strongly throughout and was in a menacing third as the field turned for home.
US challenger Bridgetown held the lead heading inside the final two furlongs but Pounced wore him down late on to take the prize by three-quarters of a length.
It was a second successive victory in the race for Gosden and Dettori having teamed up with Donativum 12 months ago.
Gosden said: "I wasn't surprised he was sent off favourite because he looked good training here.
"I thought it would be awfully hard to come from behind and that something would kick off the bend and wouldn't be caught. It's not easy to come from where we did but we had a good draw, got the split and got the job done.
"Frankie and I go back a long way in California and this race has been the plan ever since he won his maiden."
Dettori said before performing his trademark flying dismount: "I was waiting for the gap and when it came, I had a good partner with me and he showed great courage.
"The great thing was I had a good draw on the rail and all week it has been the place to be."
There was no joy for the Aidan O'Brien-trained favourite Mastercraftsman in the Dirt Mile as he finished fourth behind surprise winner Furthest Land.
Breeders' Cup Juvenile Turf
1. Pounced (L Dettori) 3-1 Fav
2. Bridgetown (Robert Landry) 15-2
3. Interactif (Kent Desormeaux) 4-1
Breeders' Cup Mile (Turf)
1. Goldikova (O Peslier) 13-8 Fav
2. Courageous Cat (Garrett Gomez) 33-1
3. Justenuffhumor (Alan Garcia) 14-1
Breeders' Cup Turf
1. Conduit (R L Moore) 10-11 Fav
2. Presious Passion (Elvis Trujillo) 8-1
3. Dar Re Mi (L Dettori) 5-1
Breeders' Cup Classic
1. Zenyatta (Mike Smith) 10-3
2. Gio Ponti (Ramon Dominguez) 14-1
3. Twice Over (T P Queally) 12-1