British number three Kyle Edmund is out of the Nottingham Open after a 6-4 7-6 (7-5) defeat by Ukrainian world number 32 Alexandr Dolgopolov.
Edmund, 21, who is ranked at a career-best 68th after making the last eight at Queen's, was edged out in a tight match that featured one break of serve.
However British number four Dan Evans overcame Lithuanian world number 53 Ricardas Berankis 2-6 7-6 (7-3) 6-2.
He will face Uruguayan second seed Pablo Cuevas in the third round.
Top seeded South African Kevin Anderson is also into the last 16 after coming through a testing match with Croatia's Ivan Dodig 6-3 6-7 (5-7) 6-3.