The last time the New York Mets were at Citi Field, they were riding a much-needed wave of momentum.

When the Mets return home this week, they'll once again be tasked with trying to save a season in danger of spiraling out of control.

The Mets will look to snap their latest skid Monday afternoon when they host the Cincinnati Reds in the opener of a three-game series.

Right-hander Nolan McLean (2-3, 3.57 ERA) is slated to start for the Mets against Reds left-hander Nick Lodolo (0-1. 7.20).

Mets closer Devin Williams gave up a walk-off grand slam to Heriberto Hernandez in the ninth inning Sunday afternoon as the Miami Marlins completed a three-game sweep of New York with a 4-0 win.

The Reds haven't played since splitting a doubleheader Saturday, when they fell to the visiting St. Louis Cardinals 8-1 in the opener before earning a 7-6 victory in 11 innings in the nightcap. The scheduled series finale between the teams Sunday was postponed until August due to rain.

The loss was the fifth in the last six games for the Mets, who were slipping into a familiar slump against the Marlins and Washington Nationals even before Juan Soto missed Sunday's game due to an illness.

New York opened May by going 11-5 while outscoring its opponents 86-58 - a stretch that included a 5-1 homestand against the Detroit Tigers and New York Yankees from May 12-17 in which the Mets trailed in all of their wins.

But the Mets were outscored 28-14 by the Marlins and Nationals over the last six games, managing just two runs and 11 hits in the entire series at Miami. New York has scored two runs or fewer 23 times this season, the second-most such games in the majors behind only the Los Angeles Angels (27).

"We've got to find a way, we've got to keep going here, we've got to continue to make adjustments," Mets manager Carlos Mendoza said. "Because what we're doing right now is not good enough. As simple as that."

The walk-off win over the Cardinals Saturday night continued a potential turnaround for the Reds, who led 5-1 after five innings and squandered a 6-4 lead in the ninth before Spencer Steer raced home from third on Blake Dunn's grounder into a five-man infield

The win was the third in the last four games for the Reds, who began May with 13 losses in 17 games.

It also marked the second time in three games the Reds have scored at least seven runs.

Cincinnati, which beat the Philadelphia Phillies 9-4 on Wednesday, scored more than four runs just six times in its first 17 games of the month.

"I know it's frustrating, but we're home," Reds manager Terry Francona said about the late blown lead. "We're not on the road, so we get to keep playing. I give our guys a lot of credit because there's a lot of frustration and they played through it."

McLean is coming off the worst start of his young career last Tuesday, when he gave up nine runs (six earned) over 5 2/3 innings as the Mets fell to the Nationals, 9-6.

Lodolo didn't factor into the decision in his most recent start on May 18, allowing three runs over 5 2/3 innings in the Reds' 5-4 loss to the Philadelphia Phillies.

McLean has never opposed the Reds. Lodolo is 1-0 with a 1.54 ERA in two starts against the Mets.