José Ramírez belted his sixth career grand slam and had three hits, Will Brennan had a solo homer and the Cleveland Guardians beat the Boston Red Sox 6-4 on Thursday.

Cleveland has the best record in the American League at 18-7 and matched the second-best mark in franchise history through 25 games. The Guardians won their season series against Boston 5-2 — all in an 11-day span.

Rafael Devers had three hits and Rob Refsnyder tripled in a run for the Red Sox. Jarren Duran had an RBI single in the sixth for Boston, which went 4-2 on a six-game trip through Pittsburgh and Cleveland.

Ramírez’s slam off Chase Anderson (0-1) came one pitch after he appeared to strike out to end the second, but Red Sox catcher Reese McGuire couldn’t hold onto the foul tip. Brennan also homered in the inning as Cleveland went ahead 5-0.

After Boston scored two runs in the third and twice in the sixth to pull within 5-4, Ramírez added an insurance run in the seventh by singling, stealing second, advancing on an error by McGuire, and scoring on a passed ball.

Hunter Gaddis (1-0) was awarded the win with 2/3 scoreless innings of relief, while Emmanuel Clase pitched a perfect ninth for his eighth save.

All-Star third baseman Devers served as the designated hitter for the second straight day. He missed the previous five games with a bone bruise in his left knee and is unlikely to play the field until Saturday in Boston.

Guardians starter Triston McKenzie struck out a season-high seven in four innings, allowing two runs. Anderson gave up five runs and two homers in 1 2/3 innings.

The Guardians will next be on the road to take on the Atlanta Braves and begin a three-game series on Friday, April 25th, with first pitch at 7:20 p.m.