The latest we saw of Serena Williams, the owner of the greatest serve any woman ever threw down at Wimbledon, she was feeling woozy and serving up balls that flew like bottle rockets and produced four straight double faults in a Wimbledon doubles match. She and her sister, Venus, defaulted that match immediately, while others ran for cover, convinced it was a sign of the End Times.

This week, we’ll see if those bottle rockets will be transformed once again into the familiar, Scud-like missiles that have so helped Serena establish the rule of law in the WTA kingdom.

There’s a lot of excellent talent breaking out all over the place in the WTA, but it says something about the gap between Serena and the rest of the pack that she still holds the No. 1 ranking (and has for 74 straight weeks, the longest run since Martin Hingis' 80 weeks in 1997 and ‘98), despite faltering before the quarterfinal stage at the first three Grand Slams of the year. Are we sure those seven dwarfs surrounding Snow White weren’t really girls named Li and Simona, Petra, Aga and Maria, Genie and Angelique?

Still, the recently unthinkable now looks a lot like the possible, if not the probable: The end of the Serena Williams era in tennis. Her back is against a wall, and the walls big players back into tend to be tall. And that’s without the intrigue and gossip that followed the Wimbledon doubles default, when the venerable club’s officials declared Williams was suffering from a “viral illness.”

Now that’s a pretty unassailable diagnosis, there being merely six billion different viral illnesses out there and new ones appearing daily. The cure for the one Serena contracted appears to have been a trip to the seaside resort town of Pula, Croatia. Let’s hope the holiday also helped alleviate how “emotional and sad” Serena felt (according to a press report) in the wake of her unexpected third-round loss at Wimbledon to Alize Cornet.

The side effects of viruses are many. If there’s a bright side to what Serena has been going through in recent weeks, it’s the possibility the virus wiped out her memory of that loss to Cornet and perhaps that second-round failure at Roland Garros against Garbine Muguruza. We might as well throw in that fourth-round loss at the Australian Open to Ana Ivanovic.

Stanford looms hugely important to Williams in light of all those frustrations. It marks the start of her quest for an 18th Grand Slam title, which she’ll try to earn at the US Open. Given that Williams leaves herself as little margin for error in her scheduling as she does when she dials in a backhand winner, at this point, another shocking loss might seriously imperil her ability to win that next major. You have to wonder how long she can hold onto the top ranking if she can’t win majors and plays a limited schedule (just nine events so far this year).

Given that Williams turns 33 in less than two months, each missed chance seems like another number ticked off in a final countdown. Although Williams is done with the heavy lifting of her career, going an entire year without winning a major championship (that’s only happened three times in the past dozen years) is likely to introduce the “R” word (retirement) into her press conferences -- unfair and impertinent as it might seem.

And that conversation, as numerous top players can attest, is a pretty bad virus unto itself.