Back in March, long before Grimace and “OMG” and all of the other magic that accompanied their turnaround, the Mets suffered a sobering start to the season. The Milwaukee Brewers swept the Mets at Citi Field over Opening Weekend, dealing them the first three losses in what ended up being an 0-5 start. Then over this past weekend, with the Mets in a dogfight for a playoff spot, the Brewers took two of three from them in Milwaukee, again representing a thorn in their side. Now, the Mets have the chance to return the favor — and then some. The Mets (89-73) will face the NL Central-winning Brewers (93-69) in the best-of-three Wild Card round of the MLB playoffs, with Game 1 set to start Tuesday at 5:30 p.m. EDT. The entire series will take place in Milwaukee, where the Brewers went 47-34 this season. It’s an intriguing series, considering Mets president of baseball operations David Stearns laid much of Milwaukee’s foundation in the same role with the Brewers. As the NL division winner with the fewest wins, the Brewers have been locked into the No. 3 seed, though they didn’t find out their first-round opponent until Monday, when the Mets and Braves split a doubleheader in Atlanta and both clinched Wild Card spots. Because the Braves (89-73) won the season series over the Mets, 7-6, they got the No. 5 seed and will play the fourth-seeded San Diego Padres in the Wild Card round. The Mets are the No. 6 seed, having won the first game of Monday’s doubleheader, 8-7, in instant-classic fashion before dropping the second, 3-0, with multiple starters resting. By winning the first game, the Mets were able to save starter Luis Severino for the Brewers series rather than use him in Atlanta. Severino (11-7, 3.91 ERA) is set to start Game 1 in Milwaukee. “I’m grateful for the opportunity that the Mets gave to me and I’m really happy that I finished my year healthy and I made all my starts,” Severino told the Daily News. “From now on, whatever it takes to be advancing. If I need to pitch every five days or four days, I’ll be ready for that.” The Brewers, meanwhile, will turn in Game 1 to ace Freddy Peralta, who limited the Mets to one run over six innings back on Opening Day, striking out eight. Equipped with an upper-90s fastball and biting slider, the right-handed Peralta went 11-9 with a 3.68 ERA and ranked 11th in the majors with 200 strikeouts. The Brewers don’t boast the big-name starpower of other NL contenders — especially with 2018 NL MVP Christian Yelich out for the season after back surgery — but they are incredibly steady with a +136 run differential that ranked third in the majors. Their bullpen, led by All-Star closer Devin Williams, was the best in the NL with a 3.11 ERA, allowing them to shorten games when they take an early lead. Their starting rotation, however, ranked middle-of-the-pack with a 4.09 ERA. Frankie Montas (7-11, 4.84 ERA), who allowed two runs in four innings against the Mets on Friday, is a candidate to start a Wild Card game, as is Aaron Civale (8-9, 4.36 ERA). That could give the Mets an edge later in the short series, particularly if ace Sean Manaea (12-6, 3.47 ERA) starts Game 2 on Wednesday. The left-handed Manaea allowed five earned runs in 3.2 innings against the righty-heavy Brewers on Friday, but he has been otherwise excellent since the start of July, pitching to a 3.16 ERA over his final 17 starts. Offensively, the Brewers ranked sixth in the majors in runs scored and 10th in OPS (.729). They received a career season from shortstop Willy Adames, who set personal bests with 32 home runs and 112 RBI in his walk year, while William Contreras remained among baseball’s best-hitting catchers with a .281 average, 23 homers and 92 RBI. Not even old enough to celebrate with champagne, 20-year-old rookie Jackson Chourio lived up to the sky-high hype with 21 homers, 79 RBI and 22 stolen bases. And then there’s Rhys Hoskins, the longtime Phillies slugger in his first year with Milwaukee, whose Opening Day slide into second base drew the ire of Jeff McNeil, prompting a bases-clearing brouhaha. Hoskins hit a grand slam against the Mets on Friday, only adding the acrimony. Former Yankees and Mets catcher Gary Sanchez figures to play a role against left-handed pitching as the Brewers’ designated hitter. Between Manaea, David Peterson and Jose Quintana, the Mets may start two lefties if the series goes the distance. After falling a season-worst 11 games below .500 in late May, the Mets posted MLB’s best record the rest of the way at 67-40. The Brewers weren’t far behind by going 61-46. And although the Brewers don’t have a lineup led by Manny Machado or a rotation starring Dylan Cease like the Padres do, Milwaukee went 5-1 against the Mets this season and wield a winning pedigree that can’t be taken lightly.