ROME - Jannik Sinner's physical problems at the Shanghai Masters 1000 put an end to his match against Dutchman Tallon Grieskspoor, ranked No. 31 in ATP. A muscle problem halted the Italian, who had won the first set 7-6 in a tie break (7-3) and lost the second 5-7. In the third set, Jannik began limping noticeably. After seeking physiotherapy, the South Tyrolean withdrew from the match due to severe cramps. Success, however, went to the iron pair Sara Errani and Jasmine Paolini, who won the 500 doubles tournament in Beijing. The Italians returned to winning ways (their eighth, which…