Nadal vs Alcaraz LIVE! Latest score and updates from Six Kings Slam semi-final - Lucrative Riyadh exhibition hosts the last-ever match between Spanish duo before Nadal’s retirement

RIYADH, Saudi Arabia (AP) — Rafael Nadal starts his pre-retirement farewell tour against Carlos Alcaraz on Thursday at the Six Kings Slam, and Novak Djokovic faces Jannik Sinner at an exhibition event that awards money but no ATP ranking points and is Saudi Arabia's latest foray into tennis.

Rafael Nadal outlined his respect for Carlos Alcaraz and Jannik Sinner but encouraged the media not to compare them to him or his greatest rivals. The era of Nadal, Roger Federer, and Novak Djokovic dominating tennis and playing each other when at or near their peaks is considered by most to be the greatest the sport has ever seen.

The Six Kings Slam is an exhibition event for a half-dozen men that awards money but no ATP ranking points and is Saudi Arabia’s latest foray into tennis.

The kingdom is putting on the richest tennis exhibition in history, but its wider ambitions in the sport have contracted.

Rafael Nadal and Carlos Alcaraz do battle today for what will surely be the final time. Nadal recently announced that he will retire from tennis at the end of the season, with his final appearance coming when he represents Spain in the Davis Cup finals next month in Malaga.

The Six Kings Slam is the most lucrative exhibition tennis tournament ever, taking place in Riyadh, Saudi Arabia, as part of the country’s annual sporting season.