Sam Walker took two sets off top seed Koki Niwa before bowing out of the Austrian Open in Linz.
Walker took the first set and later levelled at 2-2, but the left-handed world No 19 was able to pull clear and win their last-64 clash.
Walker’s under-21 singles run was also ended by a Japanese southpaw as Yuma Tsuboi won 3-1, though Walker saved five match points after finding himself 10-6 down in the fourth. He also missed a game point of his own before succumbing 14-12.