World number one Jannik Sinner reached the last 16 at the ATP tounament in Halle, Germany after a three-set win over Dutchman Tallon Griekspoor on Tuesday. The 22-year-old Italian had to come from behind to win 6-7 (8-10), 6-3, 6-2 in 2 hours 22 minutes. The Australian Open champion sealed victory on his first match-point and next faces Hungary’s Fabian Marozsan. Halle functions as a warm-up for Wimbledon, with the grass grand slam beginning on July 1. Sinner’s best performance at the All England Club was reaching the semi-finals last year. Fourth seed Andrey Rublev continued his patchy form w…