Wimbledon Betting: It's taken 17 years but the Williams era is ending

All going wrong . . . Serena Williams on her way out of the French Open

Serena Williams remains favourite to win Wimbledon despite crashing out of the French Open yesterday. Ralph Ellis says don't be fooled - her reign at the top of the game is coming to a close...

It's taken 17 years, but I finally got to make the phone call to my old Daily Star sports editor yesterday and point out: "Told you so".

It was back in 1997 that he sent me to Eastbourne to do a piece on two young sisters from America who were being touted as the next big things of international tennis. The week before Wimbledon there were worse assignments. It was for once hot and sunny, the ice cream man was working overtime, and I settled down with a "99" to watch the ladies in question.

The elder girl was playing in the main draw, but got wiped out by Nathalie Tauziat in the second round. Her younger sister appeared only in a doubles game, which she also lost, and on the practice courts. They both belted the ball with phenomenal power, but it went anywhere. I chatted to their Mum, who was charming, but wrote a piece dismissing them as The Great Hypes, rather than the great hopes, of women's tennis.

Got that one wrong, then. Some 26 Grand Slam titles later, the Williams Sisters have their place in the game's history. And every few months, whenever they've added another championship to their burgeoning haul of silverware, I've had a teasing call or a text from the sports editor in question reminding me of my judgement.

Finally, the boot is on the other foot. Venus tumbled out of the French Open yesterday against 19-year-old Anna Schmiedlova, and then barely an hour or so later Serena had been humbled 6-2 6-2 by Garbine Muguruza. It was her worst ever defeat in a Grand Slam.

As shocks go, it was a massive one - but surprisingly didn't make much difference to Betfair's Wimbledon market. Already matched at 2.021/1 to be the Women's Tournament Winner, Serena remains the massive favourite - even if she has drifted to 2.526/4. At the risk of repeating a 17-year-old mistake, that's a brilliant chance to press the "lay" button.

Serena herself left Roland Garros making promises about what would come next. "I'm going to go home and work five times as hard to make sure I never lose again," she said. And it would be foolish not to remember 2012, when with troubles from a back injury she crashed out in the first round of the French and then returned to win her fifth Wimbledon title.

But she will be 34 in September and the years are catching up. She may still be on top of the world rankings, more than 4,000 points ahead of Li Na. She may still thump the ball with a power that's beyond almost every other player on the women's circuit. But this season there has been a stunning lack of consistency about her game. Twice she has failed to make the final of a non Grand Slam event - almost unheard of - and her erratic displays have cost her now both in Australia and France.

There's something else. The aura of invincibility is going. "A change is coming," said Muguruza after her win. "Some time the new generation has to come through, and I think now is the moment."

Serena still needs one more Grand Slam to match the career hauls of Chris Evert and Martina Navratilova, and five to catch Steffi Graf. At one time both achievements looked a certainty. Now, a bit like Tiger Woods chasing the Jack Nicklaus legend, they are moving further out of reach.

The Williams era has been inspiring and magnificent, but it is ending. Wimbledon will be one last chance to back my 17-year-old judgement and finally get it right!