Opening day at Del Mar racetrack and there’s a party going on

There was primping, flirting, laughing, betting, drinking — and that was before the first race went off on opening day at Del Mar.

In what has become the social event of the year in San Diego County, a crowd of 43,030, the largest to attend a horse race in California this year, showed up on Wednesday to create a party-like atmosphere complete with hats seemingly designed from an unknown civilization.

“Oh my God. Look at this,” one female track visitor said in awe of a hat that included an iron replica of the Eiffel Tower covered with flowers and feathers.

PHOTO GALLERY: Opening Day at Del Mar racetrack

The marketing mavens who have built up opening day as an event at which to be seen, make a fashion statement and network among friends and strangers couldn’t have been more pleased.

“It’s the place to be in the world today,” trainer Peter Miller said. “There’s no better party going on. I guarantee it.”

Miller horses won the first two races under jockey Joel Rosario, so you can understand his excitement.

“Pinch me. Pinch me,” he said. “This is unreal. To win back to back … this is the greatest place on Earth for me.”

Rosario won four of the 10 races. He was only dropping by before heading to the East Coast to ride at Saratoga on Friday.

“I’d love to kidnap him and keep him for the whole meeting,” Miller said.

The distinct sound of a roaring crowd as the starting gate opens to begin the first race has become rare in Southern California.

Dwindling interest has helped force the closure of the 75-year-old Betfair Hollywood Park after Dec. 22. But at Del Mar, the demographics usually missing from racetracks — young fans and women — were plentiful Wednesday.

The track’s president and chief executive, Joe Harper, will soon get to plot more marketing moves, because in 2014, Del Mar will hold its first autumn meeting after the demise of Hollywood Park. He’ll need to show Del Mar can draw crowds in November and December.

“If we do Hollywood Park numbers, I’ll jump off the roof,” he said.

In the split divisions of the $100,000 Oceanside Stakes for 3-year-olds going one mile on the turf, Gervinho and jockey Rafael Bejarano took the first division by a neck over Greeley Awesome. Rising Legend and jockey Julien Leparoux won the second division by a head over Gabriel Charles.

What’s certain is that Del Mar, with its location next to the Pacific Ocean and its pleasant summer weather conditions, has become an ideal setting for many.

“Opening day is a tradition that gets better and better,” owner Gary Barber said. “Everyone is festive and happy. It’s the way it should be in horse racing. It’s where the surf meets the turf.”

eric.sondheimer@latimes.com