Third’s a crowd: Miami’s Logan Morrison, below, is called out while intruding teammate Donovan Solano is ruled safe at third base in the sixth inning. (Katherine Frey/The Washington Post)

Ian Desmond arrived at the plate Wednesday night with two Washington Nationals teammates on and two outs in the bottom of the seventh inning. The score was tied against the Miami Marlins on a humid night with few souls still in attendance to watch the rain-soaked game. Desmond was sent a message moments before when the Marlins opted to intentionally walk Jayson Werth, the team’s best hitter.

The Marlins watched Werth deliver the game-tying home run in the previous inning, a monstrous shot to center, and wanted to take their chances with left-handed reliever Mike Dunn against Desmond. On the first pitch Desmond saw, he countered with his own message to the Marlins, drilling a single to left that scored Denard Span, the deciding run, in the Nationals’ 4-3 win.

“When I was up there, I thought they were going to walk both of us to get to [Adam] LaRoche with nobody warming in the ’pen and a lefty-lefty situation,” Desmond said. “Probably the smart move.”

The victory was the Nationals’ 13th in their past 18 games and kept their playoff hopes flickering as they stayed seven games behind the Cincinnati Reds for the second wild-card spot. At 67-65, the Nationals moved to two games over .500 for the first time since July 11. And they did so with only two innings from their ace, Stephen Strasburg, who didn’t return to the game after a 72-minute rain delay.

The bullpen provided seven innings of solid relief with some hairy situations sprinkled in. Craig Stammen delivered three strong innings and allowed one run in front of the smallest crowd of the season, an announced attendance of 24,394 that was a mere fraction of that by game’s end. In his first appearance since returning from the minor leagues, Ryan Mattheus was handed a 2-1 lead and ended the sixth inning trailing, 3-2.

The Post Sports Live crew debates whether opposing players purposefully hit Bryce Harper because they dislike him. (Post Sports Live/The Washington Post)

But Werth homered to straightaway center to start the Nationals sixth to tie the game, and Desmond delivered in the seventh. Drew Storen pitched around two base runners he allowed in the seventh inning. Then Tyler Clippard and Rafael Soriano tossed scoreless innings to preserve the victory.

“Down to really one guy in the ’pen and one guy on the bench,” Manager Davey Johnson said. “That was it.”

As a deluge of rain fell on Nationals Park in the bottom of the second inning, second baseman Steve Lombardozzi sliced a double to left field off Marlins starter Henderson Alvarez with two outs. It was enough to score Desmond from second base and give the Nationals an early 1-0 lead. Strasburg came to the plate as the falling rain mounted. Umpires signaled for play to be halted and players raced into their dugouts.

Neither Strasburg, who threw only 22 pitches, nor Alvarez would return. The delay was too long, so the Nationals turned to Stammen. Given his light workload and depending on how Strasburg feels on Thursday, Johnson said the right-hander may start Sunday.

Stammen was given a 2-0 lead in the third inning when left fielder Bryce Harper laced a double to left off reliever Ryan Webb. Third baseman Ryan Zimmerman scored from first on the hit from Harper, who has heated up again with minor adjustments at the plate. He has stood more upright in the batter’s box, been more selective and his swing less violent. As a result, Harper has a 10-game hitting streak in which he is hitting .381 (16 for 42).

Stammen ran into trouble in the fifth inning. He fired a first-pitch slider low to catcher Jeff Mathis, who entered the game hitting .189 with three home runs. Mathis dug out the pitch and deposited it over the left field fence into the visitor’s bullpen. After a visit from pitching coach Steve McCatty, Stammen stranded a runner at second base.

Mattheus relieved Stammen in the sixth inning and his struggles continued. Mattheus returned Tuesday from Class AAA Syracuse, where the Nationals sent him to iron out his mechanics and troubles on the mound. His command was off against the first batter he faced, right fielder and Nationals killer Giancarlo Stanton. He couldn’t locate his fastball so Stanton hammered the second slider Mattheus threw far over the center field fence.

Mattheus served up singles to three of the next four batters he faced, including one to Mathis that put the Marlins ahead, 3-2.

Storen, too, walked a tightrope in the seventh inning but managed to escape. He allowed a single and walk to leadoff the inning and found himself facing Stanton with no outs. Storen fell behind 2-0 and was visited by McCatty. Storen then fought back and struck out Stanton on a wicked slider. Storen completed the inning with two popouts.

“I think it’s just his general charisma,” Storen said of McCatty’s visit. “Soothing words, I think, would be another way to put it. Take a breather and reset. Obviously the inning wasn’t off to a good start, but you’re gonna have those.”

Werth erased Mattheus’s mistakes with monstrous blast to center that rivaled Stanton’s shot. On the second pitch he saw from a Marlins right-handed reliever Arquimedes Caminero, Werth, now hitting .395 with five home runs in 23 games in August, crushed the fastball over the center field fence for his 20th home run of the season, tying the score at 3.

“He’s playing unbelievable,” Desmond said. “This is the Jayson I remember playing against in Philadelphia. Grinding-type at-bats. A lot of balls hit on the barrel. Just working the count.”