Men’s tennis is undergoing a secret data revolution, with six-figure annual retainers being paid to teams of analysts hedged with non-disclosure agreements.

As Alexander Zverev said in The Daily Telegraph, “All the big guys are using data analysis, they just don’t like to talk about it. I use it a lot. It’s a big part of the game now. It’s helped me with game-plans and preparation for individual opponents, and it was particularly helpful at the ATP Tour Finals [where he beat world No 1 Novak Djokovic in the final].”

The leading agencies in this growing market include Tennis Stat and Golden Set Analytics. They are pitching for new work within the women’s game, where the idea has not yet caught on to the same extent, and quoting sums of £80,000 or more for an annual package. If you want an exclusive deal – in which your rivals cannot access the same company’s services – then the fee rises further.

The tipping point for serious analytics was at the start of the 2017 season. Roger Federer, always a far-sighted player who is prepared to invest in himself, is understood to have begun his work with Golden Set Analytics shortly before his dramatic comeback win at the Australian Open.