Wimbledon officials did not factor in humidity under the roof producing a wetter ball, slower ball.
The Centre Court roof has changed Wimbledon
The Centre Court roof has changed Wimbledon, but in ways that bring to mind the expression "unintended consequences".
Evidence is beginning to mount that games played in the closed arena are unlike others played at the All England Club.
It began with players who came out from under the roof and insisted that matches there were slower than those played outside.
After losing to Andy Murray on Saturday, Ivan Ljubicic said Centre Court with the roof closed was "by far the slowest [grass] court in the world". He spoke of being able "to step in and hit returns" of service against Murray, one of the game's big hitters.
Now, experts are lending intellectual weight to anecdotal evidence. The physicist Andy Kidger told The Daily Telegraph that higher humidity under the roof produces a wetter, slower ball.
"You've got 15,000 people inside, all breathing and sweating, and then there is the moist surface of the grass, which will be releasing more water vapour into the atmosphere," he said.
"The ball will suck in some of that water vapour and so become a little bit heavier and slower, both through the air and especially off the court. When it bounces, it will sit up nicely to be hit rather than rushing through as normal."
Also, closing the roof is a 10-minute process; water reaches the court before it is sealed.
Players also have complained of overheating under the roof, even with chilled air pumped in.
The Daily Mail quoted Steve Haake, a Sheffield University professor who said players might feel "clammier" even with a fixed temperature of 23°C. "When you play outside, there is usually a breeze of some sort, helping sweat to evaporate. You don't get that in a carefully controlled environment."
So any matches played in a closed environment might hurt the chances of the big serve-and-volley players and aid those thought of as slow-speed, clay-court specialists. To wit: as good as Rafael Nadal is on any surface, he is even more formidable on slow surfaces, and a final under a roof for the first time could make him nigh unbeatable.
More than ever, champions could be decided by how much rain falls the next six days. The forecast? A chance of rain today, but sun for the rest of the week. The big hitters hope that is the case.