WASHINGTON (AFP) — The Washington Nationals announced that they have fired manager Dave Martinez and general manager Mike Rizzo after suffering their fourth Major League Baseball loss in five games.

Shortly after the Nats dropped a 6-4 decision at home to Boston, team owner Mark D. Lerner announced Rizzo, the president of baseball operations, would be replaced by assistant general manager Mike DeBartolo and that an interim manager would be named on Monday, an off day for the club.

Lerner, in a statement released on social media, praised Martinez and Rizzo for their roles in directing the Nationals to the 2019 World Series title, but they have not enjoyed a winning season or playoff berth since.

"While we are appreciative of their past successes, the on-field performance has not been where we or our fans expect it to be," Lerner said.

"This is a pivotal time for our club, and we believe a fresh approach and new energy are the best course of action for our team moving forward."

The Nationals are 37-53, last in the National League East division, and went 7-19 in June. They are 1-4 this month and were swept at home by Boston by 11-2, 10-3, and 6-4 over the US Independence Day holiday weekend.

Martinez, hired in October of 2017, was the longest-tenured manager in Nationals history. The 60-year-old American was 500-622 with the Nats after replacing Dusty Baker, while Rizzo was in his 17th season as baseball operations boss for the club.

The Nationals have traded such stars as Max Scherzer and Juan Soto to obtain younger talent in building for the future, but have been unable to make the moves pay off with triumphs.

Martinez has spent 39 seasons in baseball as a player, coach and manager. He spent 16 seasons as a player and was an assistant coach on the 2016 Chicago Cubs World Series championship squad before taking his first managerial post with the Nats.