The York Revolution's four-game winning streak came to a screeching halt on Sunday afternoon.
Somerset exploded for a 7-0 lead after just 2 1/2 innings and was never seriously threatened after that en route to a 9-4 Atlantic League victory in front of an announced crowd of 1,364 fans at PeoplesBank Park.
York fell to 31-29 on the season, while Somerset improved to 32-27.
The Revs had won the first three games of the series vs. the Freedom Division-leading Patriots, including a doubleheader sweep on Saturday.
Melky Mesa was an offensive bright spot for York, going 3 for 3, including a pair of homers, with four RBIs and two runs scored. Mesa is now hitting .341 on the season.
Jared Mitchell added two hits and a run scored for the Revs.
Revs starter Pat McCoy (1-4) struggled, giving up seven earned runs over 3 1/3 innings. That boosted his ERA from 3.06 to 4.54.
York will next play host to Sugar Land for a three-game series starting Tuesday at PeoplesBank Park. Tuesday's opener starts at 6:30 p.m.