Nationals second baseman Daniel Murphy reaches out to catch a ball off the bat of the Cardinals’ Marcell Ozuna during Tuesday’s 6-4 loss in St. Louis. (Jeff Roberson/Associated Press)

What lingered of the Washington Nationals’ devastation after two gut-wrenching late losses did not manifest itself in any obvious way before a 6-4 loss to the St. Louis Cardinals on Tuesday night. A stand-up comedy set blared over the clubhouse speakers until control of the speakers was ceded to Gio Gonzalez, its rightful owner as the day’s starting pitcher.

“I’ll take Celine Dion if you have it,” Gonzalez joked.

“Maybe some Alanis Morissette?” teased Matt Wieters, summoning the least energizing artist he could think of as Tanner Roark chuckled over his lunch. Such is the state of this clubhouse now, not discernibly different from what it was a few weeks ago. Wallowing does not cancel the next day’s game. Until the math says the Nationals are out of playoff contention, they will come back every day and try to win each night. What choice do they have?

“The energy’s there. These guys don’t quit. And they’re going to fight to the end,” Manager Dave Martinez said. “I love them. I really do.”

But maintaining a semblance of positivity is getting more difficult because this season looks ready to teeter into free fall. Tuesday’s defeat was their third straight and fourth in five games. The Nationals are 60-60 and need to win 22 of their final 42 games to finish above .500 for the season — far more to make any kind of push. They trail the Atlanta Braves by eight games in the National League East.

Their bullpen, decimated by injuries, was dealt another blow Tuesday when Ryan Madson landed on the disabled list with back trouble. But the bullpen was not the problem Tuesday. For the first time in his 11-year career, Gio Gonzalez surrendered a home run to the opposing pitcher — a two-run blast from John Gant in the second. Gant had not reached base in the majors before.

Gonzalez continued to struggle after that, and hit trouble again in the fourth. He walked two batters, then allowed a double that scored them both. By the end of the fourth inning, the Nationals trailed by five. Martinez pulled Gonzalez (five runs in four innings) for a pinch hitter in the top of the fifth. The outing marked the second time in three starts Gonzalez failed to pitch at least five innings. He allowed at least five earned runs for the third time in his past five.

“It’s tough to say, but this game was determined on a home run from a person you didn’t expect to hit a home run,” Gonzalez said. “ . . . unfortunately, I’m not doing my part as one of the starting pitchers.”

If the emotional and mental toll of their recent losses did not manifest itself in the clubhouse, it seemed to finally emerge on the field, where the Nationals looked lifeless early. Through four innings, their only hit was Wieters’s double to right center.

Then Juan Soto doubled to start the fifth, continuing his emergence as one of the season’s few bright spots. Wieters singled him home for the Nationals’ first run. That Wieters is finally hitting qualifies as a bright spot, too. But it is a testament to the discombobulation of this team that his emergence, along with much improved performances from Ryan Zimmerman, Daniel Murphy, and even Bryce Harper, has hardly made a difference to the Nationals’ record.

Gant left the game in the sixth inning, and two innings later, the Nationals made their nightly push. Say what you will about their results, about the cliched nature of Martinez’s nightly assertions that this team doesn’t give up, but they certainly do not roll over. Lately, they are clinging tightly to that fact.

“I really think we’ve been playing good baseball,” Murphy said. “The fact that we haven’t got our reward does not inhibit the fact that we’ve been playing good baseball.”

With the Nationals down 6-1 in the eighth, Harper hit his 30th home run, a two-run shot that slid barely over the wall in the left field corner. Then Anthony Rendon doubled, Soto walked, and Murphy singled him home, at which point the Nationals brought the go-ahead run to the plate in Matt Adams. He struck out, marking another close call for a team that has absorbed too many to count — but enough to make a person wonder what exactly derails them by such a small margin.

“You come out here to win ballgames and when you lose, it’s tough,” Harper said. “ . . . It doesn’t really feel good if you go out there and you lose by one run, or you’re down and you come back and you still lose the game.”

If one single issue were dooming this team — if the lineup never hit or the rotation never pitched, if the clubhouse were filled with more fights than playoff soundtrack banter, if the rookie manager did not have the respect of so many key veterans — the whole thing would be easier to fix. Presumably, someone would have fixed it by now.

But Tuesday night, as in so many other Nationals losses this season, a clear common denominator revealed itself again. Gonzalez couldn’t keep his team in the game early. Then the offense couldn’t quite claw back late. A veteran player did not play to his potential in an important spot and forced his teammates to overachieve to pick up the pieces — something that has happened too regularly, with too many culprits, for a variety of reasons. Sometimes, losing is that simple.