Roger Federer set tongues wagging last month when he said tournament directors like uniformly slow courts because they increase the chance of a final between superstars Carlos Alcaraz and Jannik Sinner.
World number three Alexander Zverev agreed, saying tournament directors “obviously want Jannik and Carlos to do well every tournament”.
The top two in the world have indeed met in the final of the past five tournaments they both entered – and they have been played on clay, grass and hard courts.
There is a strong argument to say they would also prevail on ice and sand, but there is no doubt court speeds have become much more uniform over the past 20 years.
There were “two completely separate tours” in the 1980s and 1990s, according to former British number one Jeremy Bates: those who played on the clay, and those on the fast courts.
But are Federer’s instincts backed up by the data? BBC Sport takes a look at the numbers and asks the tournament director in Cincinnati whether a slow court makes sound business sense.