Serena & Venus Williams ‘In Training’ With Cocktails And Dancing Till 3 AM!

Serena Williams, Venus Williams

Tennis star SERENA WILLIAMS and her sister, VENUS, are partying their way to Wimbledon – as caught in exclusive National ENQUIRER photos!

Insiders worry the top-ranked tennis players are heading for more embarrassing meltdowns at the year’s biggest tournament!

“Venus was completely blotto,” a source told The ENQUIRER. “She was stumbling around, wobbling, talking and laughing!”

While a source close to Serena insisted she wasn’t drinking, our eyewitness said the sisters didn’t quit partying until the wee hours of the morning at Palm Beach nightclub Cucina Dell’ Arte on June 21 – just eight days before the start of Wimbledon!

“You’d think they’d both be training for Wimbledon with a week to go! Instead, they didn’t leave until long after 3 a.m.!” our source said.

These photos are especially disturbing after Serena’s embarrassing performance at last year’s Wimbledon.

First, she suffered a shocking loss in the third round of the singles championship to a far inferior opponent.

That was followed by a sudden breakdown in a doubles match with her sister, as an unsteady Serena staggered around the court before abruptly forfeiting.

Fans whispered that Serena, 33, was drunk, hungover or pregnant – although she later claimed illness. She was also shaky in last month’s French Open, but managed to earn the Grand Slam title.

Las Vegas bookmakers continue to have Serena as the favorite to win Wimbledon at 7-to-4 odds – but these ENQUIRER pics will definitely have their interest, plus the attention of Serena’s competitors!