WIMBLEDON, England -- There was a major Centre Court upset at Wimbledon on Wednesday, and it involved players who weren't even playing.
When event officials released the schedule for Centre Court on Thursday, Caroline Wozniacki was listed as the featured women's player for the day.
Normally, it wouldn't matter much. But Centre Court assignment has a little extra prestige this Thursday, because the queen is making a rare visit to Wimbledon. Known more for her love of horses and dogs than any interest in tennis, she hasn't turned up here since the 1977 women's final, when Virginia Wade lived up to the occasion and gave Britain a home victory on Wimbledon's 100th anniversary.
The royal visit is just a royal pain to some, but the players see it as a nice novelty, meaning that a spot on Centre is a little more coveted than usual.
The rest of the schedule is as expected. Andy Murray, the nation's hope, was certain to get the nod. "I think there's a good chance I'll play the first match on the Centre Court, so I'll get a chance to play in front of the queen," he correctly guessed after his first-round win. "Then maybe after the match I'll get the chance to meet her."
And all expected Williams' match against Anna Chakvetadze to be the women's pick, though Sharapova's contest with Ioana Raluca Olaru was also a potential choice. But who saw Wozniacki versus Kai-Chen Chang coming?
Wozniacki was also part of a Centre Court scheduling controversy last year, when her match against fellow babe Maria Kirilenko and Victoria Azarenka versus Sorana Cirstea were played on Centre Court on consecutive days while top seed Dinara Safina and Williams played on smaller courts. "Good looks are a factor," a Wimbledon spokesperson said at the time.
With Serena not playing Wednesday, there was no opportunity to get her reaction to the scheduling, and older sister Venus Williams was guarded in her reaction. "I don't know," she said when asked whether Serena would be disappointed. "I guess you'll find out tomorrow when you ask her."
But maybe that's why Serena was hedging her bets as she talked excitedly a couple of days ago about potentially playing in front of a royal audience.
"I'm almost speechless because -- I mean, hopefully I'll even get to play in front of her. If not, I'll be fine because I don't want to get too nervous," Serena said.
"I think it's cool. She hasn't been here in how long? … She's missed some generations of incredible tennis players. To be in a new generation where she is going to come out and see, and even to be on the grounds and playing on that day I think is a real honor."
Serena had also promised the queen a curtsy "she'll definitely never forget." Maybe that gave tournament officials pause when they went to plan the schedule.
"I was going to curtsy today on the court afterwards, but I think I flubbed it. So I'm definitely going to work on it a little more. I'm trying to tone down my wrist action," said Williams after her first-round win.
Still, with the queen also scheduled to meet some players afterward, Serena may still have a chance to make use of all that practice.
Assuming the visit isn't anticlimactically brief, Centre Court isn't the only thing the queen will have to look at -- a lot of things have changed at Wimbledon since her last visit 33 years ago. Court 1 and Court 2 are both new, the Crow's Nest and water tower are gone, and there's no more standing room on the stadium courts for the plebeians. Modern developments include the debenture holders, official clothing sponsors and video screens. Oh, and the roof, ensuring that Her Majesty doesn't have to twiddle her thumbs in case the weather also decides to keep with tradition and rain.
Another thing that's changed is that players no longer have to bow and curtsey to the Royal Box when they enter and leave Centre Court. Hence the minor frenzy around reviving the custom for the queen's visit on Thursday.
The tournament is leaving it up to the players to decide whether to do the traditional calisthenics, which seems like a recipe for confusion. Imagine poor Jarkko Nieminen standing at the door, debating whether Britain's head of state should get a bow from Finland's No. 1 player.
In reality, it won't be that random. Officials will probably have a word with the players beforehand to find out what they plan to do, and have someone take them through a practice run if necessary.
Murray initially wouldn't commit to a course of action, wanting to avoid getting into a "ridiculous argument" about the issue. But the tabloid reaction forced him to confirm that, yes, he will definitely bow.
"The plan was to bow to the queen, as everybody would," he said. "It's just [I] wanted to get the right etiquette for what we were doing on the court.
"I don't know what I'll say exactly. I'll probably be a little bit nervous, understandably. I guess I don't want to mess up at all."
There's no question Nadal will follow the protocol. The Spaniard, whose first move after winning the French Open earlier this month was to acknowledge the presence of the queen of Spain, was asked before the tournament whether he would be bowing to Britain's monarch. "Sure," he replied. "I respect everything.
The pomp and circumstance is bound to be a distraction, but likely not a giant one. "I hope it doesn't affect me in the match," Murray said. "But then, you know, it is our job to be able to concentrate and to focus, not let things that are going on off the court distract you."
And what are Wozniacki's plans? It never occurred to anyone to ask her.
Kamakshi Tandon is a freelance tennis writer for ESPN.com.