The New York Mets have bigger things in mind than earning extra-inning wins in both ends of a doubleheader for the first time in almost 40 years.

But resourceful victories such as the ones the Mets recorded Saturday are essential in building a championship-caliber base for a franchise looking to win the World Series for the first time since 1986.

The Mets will seek to complete a four-game sweep of the host Chicago Cubs on Sunday.

Left-hander David Peterson (5-2, 3.48 ERA) is slated to take the mound for the Mets against right-hander Adrian Sampson (0-1, 3.33).

The Mets swept Saturday’s doubleheader, recording a 2-1, 11-inning win in the opener and escaping with a 4-3, 10-inning win in the nightcap.

It was the first time the Mets swept a twinbill with a pair of extra-inning victories since July 31, 1983, when they beat the Pittsburgh Pirates 7-6 in 12 innings in the opener before winning 1-0 in 12 innings in the second game.

The win in Saturday’s nightcap underlined the resourcefulness displayed this season by the Mets, who are 58-34 — the furthest they’ve been over .500 since the end of the 2006 season — and 2 1/2 games ahead of the Atlanta Braves in the National League East.

The Mets scored two runs without hitting the ball into the outfield in the top of the 10th Saturday before Yoan Lopez escaped a bases-loaded jam by getting Frank Schwindel to hit a scorched grounder to third baseman Eduardo Escobar, who began the game-ending double play by stepping on third.

Lopez, who was added to the roster as the 27th man before the doubleheader, threw 38 pitches over two innings and was the last pitcher manager Buck Showalter planned to use as he tried to conserve the bullpen for Sunday’s finale.

“Those are games that good teams win,” Showalter said. “Just real proud of everybody. There were so many opportunities there to give in (and) say OK, something may not be there or whatever.”

The losses continued a discouraging season for the Cubs, whose nine-game losing streak isn’t even their longest of the first half. Chicago dropped 10 in a row from June 4-16.

The Cubs squandered chances to win both games Saturday. In the opener, Nelson Velazquez was at third base with none out in the 10th before Adam Ottavino set down the next three batters.

The Mets scored what proved to be the winning run in the 10th inning of the nightcap when Francisco Lindor trotted home after Cubs pitcher Daniel Norris threw the ball away while trying to pick Pete Alonso off second base.

Still, Cubs manager David Ross remained optimistic even after a frustrating day in which he was ejected from the first game and left fielder Ian Happ was tossed from the second game for arguing with plate umpires Ramon DeJesus and John Tumpane, respectively.

“We’re going to find a way to win,” Ross said. “These guys keep giving effort every single day — day-night doubleheader against a first-place team with a $300 million payroll, and these guys are fighting their (rear ends) off.”

Peterson took the loss Tuesday night when he gave up two runs over 5 1/3 innings as the Mets fell to the Atlanta Braves 4-1. Sampson also absorbed a defeat Tuesday after surrendering three runs over 5 1/3 innings in the Cubs’ 4-2 loss to the Baltimore Orioles.

Peterson is 1-1 with a 2.89 ERA in two career starts against the Cubs. Sampson has never opposed the Mets.

–Field Level Media