Daniel Murphy hit two home runs to back Tanner Roark, and the Washington Nationals won the opener of a series between division leaders by beating the Chicago Cubs 4-2 on a chilly Friday afternoon.

With the game-time temperature at 63, Murphy hit a two-run homer in the first and connected off Kyle Hendricks leading off the sixth for a 3-0 lead.

Roark (9-7) didn't allow a run until Javier Baez chased him with a two-run homer with one out in the seventh. Roark allowed five hits while improving to 3-1 in his past four starts.

Hendricks (4-4) gave up three runs and five hits in seven innings. Chicago has lost three straight after winning 14 of 17 following the All-Star break.