WASHINGTON -- The Washington Nationals fired pitching coach Derek Lilliquist on Thursday night.

Minor league pitching coordinator Paul Menhart was promoted to replace Lilliquist. General manager Mike Rizzo made the announcement moments after the Nationals beat the St. Louis Cardinals 2-1 in a game with a starting time delayed 2 1/2 hours by rain.

"We felt that both the rotation and the bullpen, we thought that we had some flaws in there," Rizzo said. "We thought that there [were] preparation issues in there, and we thought that we wanted to get a new message and a new voice."

Rizzo reiterated his support for manager Dave Martinez and said the two made the decision together.

The victory Thursday prevented a four-game sweep and improved Washington's record to 13-17.

Despite an imposing rotation highlighted by three-time Cy Young Award winner Max Scherzer, three-time All-Star Stephen Strasburg and $140 million free agent Patrick Corbin, the Nationals began the day with a 4.95 ERA that ranked 13th out of 15 NL teams.

Washington's relievers are last in the NL with a 6.02 ERA, though the bullpen has improved of late.

"I was surprised, to be honest," closer Sean Doolittle said after earning his fourth save.

"I know that the bullpen didn't get off to the start that we wanted to, but here kind of over the homestand over the last week or so things have really fallen into place nicely. The starters all year long have done really, really well."

Lilliquist, the Cardinals' pitching coach from 2013 to 2017, was hired after Martinez replaced Dusty Baker.

Menhart has served as the team's minor league pitching coordinator since 2015. This year marks his 14th season in the Nationals organization.

"It's not easy," Martinez said about firing Lilliquist. "But I feel like moving forward, this is the best for the team.

"Paul Menhart, who I've known now for a couple of years, who I've talked and worked with, he brings a different kind of energy. He's positive. He's a technician. He knows analytics. A lot of our pitchers here have worked with him throughout their whole minor league careers."