PITTSBURGH — The opening scene Saturday was splendidly done and the first of several home runs for the Pirates.

Relatives of Flight 93 passengers surrounded the infield, 170 in total. Meanwhile, 200 Pittsburgh police officers, firefighters and paramedics unfurled a gigantic American flag in the outfield, and Allegheny County sheriff Richard Manning sang the national anthem.

Seats and railings were the only things inside PNC Park left unmoved, and the Pirates and Nationals topped it off by personally greeting and thanking family members who lost loved ones during the Shanksville plane crash.

Baseball offered an important diversion from reality 20 years ago, the Pirates authored a couple more special moments on the 20th anniversary of 9/11, making those in attendance proud by earning a hard-fought, 10-7 victory over the Nationals that gives them a chance at that elusive series sweep.

The Pirates (52-90) are 0 for 12 when trying to sweep a series and remain the only MLB team without one. However, they have been playing markedly better baseball of late.

They’re 10-11 in their last 21 games after losing 13 of 14. They’re also now 9-5-2 in their last 16 series at PNC Park while going 25-17 against teams outside the NL Central at home, 9-1-4 in series play against those teams.

After climbing out of an early hole, the Pirates took with a four-run sixth inning that was helped along by four walks courtesy of Nationals pitchers — part of 10 they issued for the game.

The Pirates jumped in front, 6-5, when Bryan Reynolds drew the fourth free pass of the inning, and they increased their lead to 7-5 when Colin Moran’s dribbler found a soft spot on the right side of the infield.

More self-inflicted wounds followed for the Nationals, as second baseman Luis Garcia — playing in shallow right field because of the shift — bobbled a ball hit by Ben Gamel, which allowed two more runs to score.

All in all, it was an inning that never, ever should have happened, but also one that has eluded the Pirates this season more than they’d prefer, the type of situation where the other team makes it easy on them for a change.

With the Pirates ahead, 9-5, after six, the Nationals picked up single runs in the seventh and eighth thanks to a single from left fielder Yadiel Hernandez and Ryan Zimmerman’s pinch-hit, solo homer.

Pittsburgh countered with Kevin Newman’s run-scoring double in the seventh, and they leaned on Chris Stratton to close it out in the ninth and earn the save.

For the first half of Saturday’s game, it looked very much like another lopsided loss for the Pirates. Anthony Banda entered the game in the fifth and allowed four consecutive hits, the first two doubles.

Shortstop Alcides Escobar ripped a low change-up into right-center field to score one run and extend Washington’s lead to 4-2 before right fielder Juan Soto smoked a high fastball at 111.6 mph into right field for a 5-2 edge.

Facing Josiah Gray — a talented young pitcher who was a key part of the Max Scherzer trade — the Pirates did what many have done against the 23-year-old right-hander and put a couple of balls over the fence.

After Yoshi Tsutsugo earned the Pirates’ sixth and final walk off Gray, Reynolds ambushed a middle-middle, first-pitch fastball from Gray, sending it screaming 426 feet at 110.3 mph for his 23rd of the season. The two-run homer cut the Nationals’ lead to one at 5-4.

Two batters later, Gamel put a similar swing on a fastball lower in the zone, driving it into the right-field seats to create a 5-5 tie. They were the 16th and 17th homers Gray has allowed this season in just 10 games (nine starts).

The Pirates opened the scoring in the third when Gray walked the bases loaded, and Moran tomahawked a high fastball into right field for a two-run single.

The first run, scored by Hoy Park, came across easily. It appeared that Tsutsugo was out, although after the Pirates challenged, it was determined that catcher Keibert Ruiz did not give Tsutsugo anywhere to slide and had not yet received the throw — the Buster Posey Rule rendering Tsutsugo safe.

Washington answered with a bases-loaded strike of its own in the fourth. Wil Crowe, pitching against his former team for the first time, allowed three consecutive singles to start. It looked like Crowe might wiggle out of trouble when he struck out Hernandez and third baseman Carter Kieboom, but Ruiz cleared the bases with a double into the right-center gap.

It was a tough break for Crowe, who actually pitched decently and struck out six over four innings. Ruiz simply went down and got a curveball that absolutely would not have been called a strike.