Washington, DC -- (Sports Network) - The Washington Nationals fired manager Manny Acta and named bench coach Jim Riggleman as his interim replacement on Monday.

The lowly Nationals made Acta the scapegoat as the club compiled a league- worst 26-61 record through the first half of the season.

"This was a decision that we finalized over the weekend with the management team," said the club's acting general manager Mike Rizzo at Monday's press conference. "We feel the team has underachieved. We feel we have a better ballclub than we have shown on the field. We feel with a different voice and possibly a different feel in the clubhouse that we can have a more successful second half of the season."

Washington recorded a paltry 158-252 mark in Acta's two-plus years at the helm. After he guided a rebuilding franchise to a relatively respectable 73-89 campaign in 2007, the Nats finished with a league worst 59-102 record last season.

Before joining the Nationals in November of 2006, Acta was perhaps best known for managing the Dominican Republic to a berth in the semifinals of the inaugural World Baseball Classic in 2006. He has managed or coached third base in the NL East each season since 2003.

This will be Riggleman's fourth stint as manager. He owns a 522-652 combined record with the Padres (1992-94), the Cubs (1995-99) and the Mariners (2008).

His interim stint in Seattle last year also began mid-season after he took over for the fired John McLaren in June. The Mariners went 36-54 under Riggleman, who joined Washington in the offseason after Seattle hired Don Wakamatsu as their full-time manager in the offseason.