Japan's Yoshihito Nishioka retired in his fourth round match at the BNP Paribas Open on Wednesday due to back pain.Nishioka looked sluggish from the outset and dropped the first set 6-4 to Serbia's Miomir Kecmanovic despite taking medication and a time out to receive a massage from a trainer. He pulled out partway through the first game of the second set.The 23-year-old Japanese had booked his round of 16 match with the Serbian, who reached the main draw as a lucky loser, after rallying past Canada's Felix Auger-Aliassime 6-7(2), 6-4, 7-6(5) on Monday."I wasn't worn out or anything (by the …READ FULL ARTICLE
