Carlos Gomez hit a go-ahead three-run homer in the eighth inning Thursday afternoon for the host New York Mets, who took advantage of the struggling Washington Nationals bullpen yet again in a 6-4 win that completed a four-game sweep.

The Mets, who endangered manager Mickey Callaway's job by getting swept by the Miami Marlins last weekend, swept a four-game series from the Nationals/Montreal Expos franchise for the first time since 1991.

The Nationals have lost five straight to fall 12 games under .500 for the first time since the 2010 season.

Mets right-hander Robert Gsellman (1-0) entered in the eighth inning and blew a 3-1 lead. He walked Juan Soto with one out, gave up a two-out RBI double to Yan Gomes and a two-RBI single to pinch hitter Gerardo Parra as Washington went in front 4-3.

But the Nationals, who entered Thursday with the worst bullpen ERA (6.89) in baseball, imploded yet again in the bottom of the inning.

Wander Suero (1-4), who relieved starter Stephen Strasburg, gave up a leadoff pinch-hit double to Dominic Smith before striking out Todd Frazier and Pete Alonso and intentionally walking Wilson Ramos.

Gomez, who played for the Mets as a rookie in 2007 before rejoining the team on a minor league deal in March and earning a call-up last Friday, followed with the first homer of his second stint with the team to make the score 6-4.

Edwin Diaz earned his 12th save with a perfect ninth.

It was the third straight game in which the Mets came back against the Nationals in the eighth inning. On Tuesday, Alonso launched a game-tying homer in the eighth before Amed Rosario delivered a game-winning single in the ninth inning of a 6-5 victory. On Wednesday, Juan Lagares hit a go-ahead three-run double and Rajai Davis added a pinch-hit, three-run homer in a 6-1 win.

Lagares lofted a sacrifice fly in the fifth for the Mets' first run. The Nationals tied the game in the top of the sixth when Soto doubled and scored when New York second baseman Adeiny Hechavarria threw the ball away on a bunt by Brian Dozier.

The Mets went back ahead in the bottom of the sixth, when Alonso hit a sacrifice fly and Ramos drove home Frazier with an infield single.

Ramos and Gomez each had two hits for the Mets. Soto missed the cycle by a homer for the Nationals.

Mets starter Steven Matz allowed just one run despite allowing 13 baserunners (10 hits, two walks and a hit batter) over six innings. He struck out seven. Strasburg gave up three runs (two earned) on five hits and two walks while striking out five over seven innings.

--Field Level Media