The 4-year-old filly is the stablemate of defending champion Zenyatta, who skipped the race to run in Saturday's $5 million Classic against the boys.
Both horses are trained by John Shirreffs.
Ridden by Garrett Gomez, Life Is Sweet ran 1 1-8 miles in 1:48.58 and paid $18.20, $8 and $5 at 8-1 odds. She was the fourth longshot to win Friday at Santa Anita.
Mushka returned $12.80 and $6.40, while Music Note was another length back in third and paid $3.20 to show. Careless Jewel, the 9-5 wagering favorite, romped to the early lead before fading to last in the field of eight.
The six Breeders' Cup races went off without defending Ladies' Classic champion Zenyatta, who was back in her barn awaiting Saturday's $5 million Classic against the boys. She will put her 13-0 winning streak on the line in the 1¼-mile race, the richest in North America.
It was the second consecutive Breeders' Cup to be run on Santa Anita's synthetic Pro-Ride surface, which kept stellar filly Rachel Alexandra away. She was 8 for 8 this year, including three wins over male horses, one of them in the Preakness. But her owner Jess Jackson doesn't like synthetics, so he shut down the Horse of the Year favorite.
Man of Iron opened the card with a thrilling nose victory over 9-year-old gelding Cloudy's Knight in the $500,000 Marathon, the day's only race featuring males.
Man of Iron covered 1¾ miles in 2:54.11 under John Murtagh, giving Irish trainer Aidan O'Brien his fourth career Breeders' Cup victory. The 3-year-old paid $14.80 to win in his U.S. debut after running exclusively in Europe.
Rosemary Homeister Jr. barely missed becoming the second woman to ride a Breeders' Cup winner, losing the photo finish by a bob of her gelding's head.
Midday gave Europe its other victory, winning the $2 million Filly & Mare Turf by a length and snapping an 0 for 6 streak in the Breeders' Cup by veteran European trainer Henry Cecil.
Ridden by Thomas Queally, Midday ran 1¼ miles in 1:59.14 and paid $6.60 to win.
She Be Wild charged along the rail to win the $2 million Juvenile Fillies by three-quarters of a length under Leparoux. She ran 1 1-16 miles in 1:43.80 and paid $16.80 to win, and improved to 4 for 5 on synthetic surfaces.
It was trainer Wayne Catalano's second career Breeders' Cup victory.
The $1 million Juvenile Fillies Turf was won by Tapitsfly, who held off Rose Catherine by a half-length. With Robby Albarado aboard, Tapitsfly ran one mile in 1:34.25 and paid $21.60 to win.
Informed Decision won the $1 million Filly & Mare Sprint by 1¼ lengths over defending champion Ventura, giving Leparoux his second win of the day. The 4-year-old gray filly covered 7 furlongs in 1:21.66 and paid $8.80 to win.
Trainer Jonathan Sheppard scored his first Breeders' Cup victory on the day, to go with a second by Cloudy's Knight and a third by Forever Together in the Filly & Mare Turf.
Ventura was sent off as the 4-5 wagering favorite. She is trained by Hall of Famer Bobby Frankel, who has run his stable by phone most of the year as he battles an undisclosed illness.