Roger Federer set tongues wagging last month when he said tournament directors like uniformly slow courts as they increase the chance of a final between superstars Carlos Alcaraz and Jannik Sinner.
The world number three Alex 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.