Ian Demond applies the tag to New York’s Matt den Dekker, who is called out attempting to steal second in the sixth inning. (Jim McIsaac/Getty Images)

At this juncture of the baseball calendar in 2007, back at the launching point of his career, Jayson Werth faced the same grim odds the Washington Nationals know now. At the dawn of the Philadelphia Phillies’ mini-dynasty, Werth helped them erase a seven-game deficit in the season’s final 17 games and crash the playoffs. “I can see it,” Werth said. “I know it’s possible. I’ve done it.”

Having done it, Werth also understands how difficult it will be to finish the desperate surge of which he has become the driving force. On Tuesday night, Werth lifted the Nationals to a 6-3 victory over the New York Mets at Citi Field with a performance that fit into his blistering past two months like a puzzle piece. Werth went 3 for 4 with two doubles and his 23rd home run. As summer cedes to fall, Werth could win a batting title, land in the top five of an MVP vote or maybe even put a scare into the Cincinnati Reds. Did you think he would be a liability? It turns out he may be the best hitter in the National League.

As Werth has produced perhaps the finest stretch of his career at 34, the Nationals have kept their playoff chances on life support. The Nationals’ fourth straight victory pushed them to a season-high six games over .500 at 75-69. As the Reds lost to the Chicago Cubs, the Nationals trimmed their deficit in the race for the NL’s second wild-card spot to six games with 18 to play.

“It’s not over,” Werth said. “Nothing is over yet. But we’re in a bad spot, that’s for sure.”

On Tuesday night, Werth received help from a stable of teammates. Jordan Zimmermann claimed his league-leading 17th win with five uneven innings. Four Nationals relievers pitched scoreless innings, culminating with Rafael Soriano’s 40th save of the season. Wilson Ramos’s cannon arm wiped out two base stealers in the nip-and-tuck late innings. Denard Span extended his hitting streak to 21 games with a double down the first base line, Adam LaRoche smacked his 19th homer to left-center field and Scott Hairston put the game on ice with a two-run, pinch-hit homer in the ninth.

But it was Werth, with a continuation of his blistering second half, who led them. Werth entered Tuesday leading the NL in on-base-plus slugging percentage and slugging percentage and trailing Atlanta Braves third baseman Chris Johnson by five points in the batting race. Werth raised his batting average to .328, and since the all-star break he has hit .370 with an OPS near 1.100. There are many reasons the Nationals have won 21 of 30 games, and the first is their woolly, 34-year-old right fielder.

“A leader ripping the cover off the ball,” Zimmermann said. “Every time he gets up there, it seems like he’s going to hit a double or a home run.”

Werth and the Nationals have played their best once the season felt lost and pressure faded. They may not make the playoffs, and their expectations may go unfulfilled, but they have not unraveled.

“It’s been there,” Werth said. “There’s no doubt. We just waited around too long.”

“We want to finish strong and just show everybody we’re not going to roll over and quit,” Zimmermann said. “We’re going to fight to the end.”

The Nationals have at least allowed themselves to feel a part of the playoff race, even if it’s only an illusion. Reliever Craig Stammen planned on sending former teammate and current Cub Edwin Jackson a thank you text for shutting down the Reds.

They check the standings daily. “I’m very aware,” Werth said. “I’ve been aware for a while.” Manager Davey Johnson does not like to stare at the scoreboard during games, but the standings intrigue. “I look at the almighty loss column,” he said. And there, the Nationals are five back.

“We’re finally playing the way we thought we were going to play throughout the whole season,” Stammen said. “Hopefully it’s not too late.”

Before Tuesday night, the Nationals had been unable to solve Mets starter Dillon Gee. A solid right-hander against the rest of the league, Gee morphed into a Cy Young candidate on days he faced the Nationals. He had beaten them four times in five starts with a 2.16 ERA. Less than two weeks ago at Nationals Park, Gee had held the Nationals to two runs as he pitched into the eighth inning.

Werth would not allow him to escape the first inning undamaged. Gee threw Werth a 1-0 fastball at the letters, the type of pitch he has dined out on for two months. Werth crushed it over the left field fence, and the ball rattled around the Party City Deck.

“He’s not hitting anything cheap,” Johnson said.

Werth’s next trip to the plate came with one out in the third, two batters after Span ripped a double to right. Gee tried to sneak a 2-1 slider past him, and Werth smoked it to left-center field. The ball short-hopped the wall as Span trotted home with the Nationals’ third run.

Werth struck again in the sixth. He led off with a double that skipped between center fielder Matt den Dekker and right fielder Juan Lagares all the way to the wall. Werth scored when Ramos ripped a two-out single to left field.

After Werth’s fireworks provided an early cushion, the night became about holding on. A night after Gio Gonzalez cruised to a one-hitter, Zimmermann labored through five innings. He danced around eight hits and endangered the Nationals’ 4-1 lead in his sixth and final inning.

Hairston provided relief in the ninth, and Soriano closed it out.