The St Regis Hotel in Riyadh has some new guests. Six big names in tennis, including Carlos Alcaraz, Jannik Sinner, Novak Djokovic and Rafael Nadal are in Saudi Arabia for a new tennis exhibition tournament: the Six Kings Slam. It won’t win them ranking points. But it is lucrative: the winner banks $6 million (Wimbledon’s top prize is $3.5 million). Just turning up earns $1.5 million (and a snazzy promo video where Djokovic is a wolf lord). Nadal, who retires next month, is already an ambassador for the Saudi Tennis Federation. Tennis is not the first sport to see the upside in Saudi’s willingness to spend. And it isn’t just the men – the women's professional tennis tour lands in two weeks for the WTA Finals as part of a three-year deal, despite criticism from former players including Martina Navratilova.