Rafael Nadal admitted his fitness level was well off the tour's top players after falling Thursday in straight sets to fellow Spaniard Carlos Alcaraz, who described the exhibition match as "a little bit sad".

Rafael Nadal starts his pre-retirement farewell tour against Carlos Alcaraz on Thursday at the Six Kings Slam.

The quarter-final were held on Wednesday 16 October, with Sinner beating Medvedev to set up an encounter with Djokovic a day later, and Alcaraz likewise booking his spot in a semi-final against Nadal. After the semi-finals, competitors will then have a rest day, before a final and a third-place play-off on Saturday 19 October.