NEW YORK (CNN/Money) - It looks like Barbie's in trouble again.

Barbie split from long-time beau, Ken, this year. Cali Barbie now sports a deep tan and a new Australian pal, Blaine.

Ever since Barbie and Ken went splitsville this year, sales of Mattel's (Research) flagship dolls have been flagging -- sinking 13 percent worldwide in the latest quarter and, according to market research firm NPD Group, losing their spot as the best-selling doll in Britain.

Industry watchers said Barbie needs to rev up her game -- and quickly -- if she wants to thwart some stiff competition from a gang of hip, trendy dolls known as "Bratz."

Closely held, California-based MGA Entertainment introduced Bratz in 2001, and the dolls have quickly become one of the best-selling toys in the United States, NPD said. Last year, sales of the hip hop-style dolls soared to $600 million.

The Mattel brand, which includes Barbie, had sales of about $3.3 billion last year, according to company reports, and analysts estimate Barbie accounts for more than half of all Mattel brand sales.

U.S. sales of all types of dolls totaled about $2.7 billion in 2003, according to industry reports.

"Barbie is certainly facing stiff competition from Bratz, and even from other no-name private-label dolls," said Dennis McAlpine, analyst with McAlpine Associates. "One of the problems is the lifespan of Barbie is becoming shorter and shorter. Kids may still buy Barbies, but then they quickly move on to something else."

McAlpine said Bratz appeal to kids' increasing sophistication. With names such as Jade, Sasha and Yasmin, these dolls, he said, borrow heavily from pop culture and appear to be "more relevant to kids in the way they look and dress."

Bratz dolls are hip, edgy and flaunt an urban flair.

A.G. Edwards analyst Timothy Conder said Mattel has been trying to reinvigorate its 45-year-old Barbie brand but has been somewhat slow off the mark.

Last year, Mattel introduced the "Flavas" dolls, an obvious nod to Bratz. Flavas were the same size as Bratz and were dressed with the same urban flair. These copycat dolls didn't work, though, and Mattel discontinued them shortly afterward.

"Bratz have gained a substantial foothold in the fashion-doll category. However, Mattel is responding with some good initiatives," Conder at A.G. Edwards said.

It all started with the Barbie-Ken separation this year after 43 years as a couple. As a newly single girl -- Cali (read California) Barbie, deeply tanned, with pierced ears and trendy outfits -- is hanging at the beach with a new Australian fellow named "Blaine."

"The split with Ken was a great publicity gimmick. It brought Barbie lots of attention. The attempt is to reposition Barbie as a single, independent woman and to make her attractive to an older demographic," said Jim Silver, an independent toy consultant and editor in chief of Toy Wishes magazine.

Other efforts include extending the brand into a Barbie apparel line for women, Barbie perfume for kids and entertainment properties, such as music and movies.

"I'm a little dubious of the licensing into clothes," said Conder. "For girls who are older than eight, do they really want to connect with the products and brands that they played with when they were younger?"

Silver, however, thinks Barbie sales will pick up over the holidays and into next year.

"It's important to remember that the fourth quarter accounts for over 50 percent of total doll sales. So Barbie sales could see a spike in the coming months. Also, Mattel has more initiatives in the works regarding Barbie, and they'll introduce those next year."

For those wondering whether Barbie's days as the toy store's most popular girl have vanished, McAlpine, Conder and Silver all agree that's far from happening any time soon.

Mattel could not immediately be reached for comment.