Italy's Matteo Berrettini broke down in tears after an abdominal injury forced him to retire from his opening ATP Finals match against Alexander Zverev, casting doubt over his participation for the rest of the season-ending tournament. Olympic champion Zverev was awarded a win after Berrettini pulled out injured early in the second set, with the German leading 7-6(7) 1-0 on Sunday. Berrettini was sidelined for two months due to an abdominal injury he suffered at the Australian Open in February. The 25-year-old was