Three weeks from Monday the Mets will either be preparing for a National League playoff series or cleaning out lockers to begin their offseason.

Whether they reach October will hinge largely upon starting pitching, with the bullpen also hardly immune from worry. The lineup is by far the least of the Mets’ concerns.

A fruitful offensive stretch continued Sunday with a 17-hit beatdown that gave the Mets their fourth victory in five games, 14-1 over the Phillies at Citi Field.

Dominic Smith and Pete Alonso were the hitting stars. Smith’s contribution was a 4-for-5 performance with three doubles and three RBIs, and Alonso blasted two homers. Jeff McNeil, Brandon Nimmo and Wilson Ramos also homered, ensuring the Mets wouldn’t waste another superb Jacob deGrom start.

“I look at our lineup top to bottom and I always view it as if I’m pitching against our guys,” deGrom said. “That is a tough lineup top to bottom. The guys are doing a great job of putting together good at-bats and driving in runs when we need to. We had a little stretch where we weren’t. We had a little stretch where the pitching wasn’t doing too well, but we are trying to put it all together right now.”

The Mets, who will send David Peterson to the mound Monday against Zack Wheeler in the series finale, moved within 2 ¹/₂ games of the Phillies for second place in the division, which carries an automatic postseason berth in this year’s expanded format. The Mets (19-22) were two games behind the Rockies in the loss column for the second wild card as Colorado began play Sunday.

Smith was asked about the possibility of a team qualifying for the postseason with a losing record.

“I don’t pay attention to that type of stuff,” Smith said. “I don’t even know what our record really is. I know we have a job at hand and that is to win ballgames. I know we’re not at .500. We want to get to .500 and go from there.”

DeGrom (3-1) allowed one run on three hits with 12 strikeouts and two walks over seven innings and lowered his ERA to 1.69. The Cubs’ Yu Darvish might be his biggest threat in trying to win the Cy Young Award for a third straight year. Darvish began Sunday as the NL leader with a 1.44 ERA. But deGrom’s 70 strikeouts lead the league. Darvish is third with 63.

DeGrom allowed a solo homer to Andrew Knapp in the second before settling in and holding the Phillies to one hit for the remainder of his outing.

The Mets turned the game into a runaway with seven runs in the seventh, when Alonso homered for the second time and Ramos cleared the right-field fence. The multi-homer game was the sixth of Alonso’s career.

“I know this team has the capability of going on a tear and all of us have been talking about it for a long time,” Alonso said. “I feel we are going to make a real good push at it.”

Andres Gimenez stroked a two-run single in the fourth against Aaron Nola that extended the Mets’ lead to 4-1. It continued a surge for the rookie, who for now at least has displaced Amed Rosario as the primary shortstop. Gimenez is 5-for-11 in this series after he delivered his first major league homer last week.

Alonso’s first homer of the game, a shot off the façade of the second deck in left, gave the Mets a 2-1 lead. Alonso’s homer in the eighth gave him four homers in his last four games. He leads the Mets with 10 homers.

“We have an important stretch of games and I want to be my best to help this team win and get into the playoffs,” Alonso said.

Smith’s RBI double in the first accounted for the Mets’ first run, after Conforto doubled. Nimmo had led off with a single, but was thrown out attempting to steal second.

“I think today we didn’t chase,” Smith said. “That is when [Nola] gets a lot of success, when guys expand their zone and chase. We were able to get him over the middle of the plate and not try to do too much and put good swings on the ball.”