Italy's world number Jannik Sinner suffered a surprise 7-6 2-6 6-3 defeat to Jakub Mensik in the quarter-finals of the ATP 500 tournament in Doha on Thursday.     The 24-year-old, who was playing his first tournament since losing to Novak Djokovic in the Australian Open semi-finals last month, found it hard to get cope with the 16th-ranked Czech's powerful serves.     It was the biggest scalp of 20-year-old Mensik's career.     ALL RIGHTS RESERVED © Copyright ANSA

Tag-uri: Italia Australian Open