BOSTON — Angel Martínez homered and Joey Cantillo threw five one-hit innings in a bulk relief role as the Cleveland Guardians clinched a playoff spot for the third straight year with a 1-0 win over the Boston Red Sox on Thursday night.

Cleveland is guaranteed at least an American League wild card and retains a one-game lead over the Chicago White Sox in the AL Central. The division winner is likely to earn the No. 2 seed and a bye into the Division Series.

Chicago has the head-to-head tiebreaker.

Cleveland starter Daniel Espino threw one inning before giving way to Cantillo (11-9), who allowed one hit with four strikeouts. He’s now thrown 15 straight scoreless innings since being removed from the rotation.

Martínez hit his 18th homer of the season in the second inning. All-Star closer Cade Smith struck out the side in the ninth for his major league-leading 41st save.

While the Red Sox clinched a playoff spot for the second consecutive season earlier this week, they are still looking to firm up their seed. Boston leads Chicago by three games for the AL’s second wild card, which would be the No. 5 seed and travel to face No. 4 New York in the best-of-three series.

Red Sox starter Ranger Suarez (8-5) gave up one run over five innings with five strikeouts. Boston had two hits and was shut out for the eighth time this season.

Red Sox center fielder Ceddanne Rafaela returned to the lineup one night after leaving Wednesday’s game with right hamstring tightness.

Up next

Guardians: RHP Gavin Williams (14-8, 3.63 ERA) is listed as the probable starter as Cleveland opens a three-game series in Kansas City on Friday.

Red Sox: Host the Chicago Cubs for a doubleheader on Friday. The Sox had not named a starter for either game.