PITTSBURGH -- The Pirates were six outs away from an encouraging win in Game 2 of Friday’s seven-inning doubleheader at PNC Park. Chad Kuhl was outstanding for five innings, and Bryan Reynolds gave them a lead in the top of the fifth by launching a two-run shot that bounced into the Allegheny River.

Nine batters, two errors and six unearned runs later, the Pirates were three outs away from one of their most exasperating losses in a season full of them.

• Box score

It wouldn’t be accurate to say the Pirates went down quietly, because their frustration boiled over and mild-mannered catcher Jacob Stallings was ejected in the top of the seventh. But the Bucs couldn’t bounce back from their mistake-filled sixth and lost, 7-2, to complete the Cardinals’ doubleheader sweep.

It was the Pirates’ 10th defeat in their last 11 games and their 36th in 51 games this season. And this one didn’t sit well for a variety of reasons, with some annoyance directed at themselves and some elsewhere.

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“Everything kind of snowballed,” manager Derek Shelton said. “It was an ugly inning.”

Let’s start from the top.

Kuhl cruised into the sixth inning, having soaked his problematic right index finger in lime juice for the last several days at the behest of assistant athletic trainer Ben Potenziano. That healed his finger, and his fastball command returned after a rough outing in Kansas City. The right-hander allowed only one run on five singles in his first five innings, struck out six on the night and didn’t walk any of the first 19 hitters he faced.

Kuhl thought he struck out Tommy Edman, the Cardinals’ first batter of the inning, too. Edman took a full-count slider that crossed the middle of the plate at the bottom of the zone.

Home-plate umpire Jeremie Rehak called it ball four. Kuhl wasn’t having it. That call was also the genesis of Stallings’ ejection, because he took a sinker located in a similar spot for a called third strike in the seventh.

“It was just a blatant missed call. Just kind of unacceptable,” Kuhl said. “Especially the slider -- we talk about this all the time as pitchers, the ones that are never a ball and never end up a ball. Just unacceptable.”

Kuhl nearly struck out Paul Goldschmidt, the next hitter. Goldschmidt was late on a high fastball -- so late, in fact, that his bat hit Stallings’ glove as the backstop was getting himself in position to throw the ball to second base. Goldschmidt took first on the catcher’s interference call.

“So I start that inning with two strikeouts and we have guys on first and second somehow,” Kuhl said. “It’s just kind of an unfortunate, weird start to a really weird inning.”

Then came what Kuhl called his “only true walk” of the night, a four-pitch free pass to Brad Miller. Kuhl was trying to work carefully to the left-handed-hitting Miller with a one-run lead.

Kuhl then exited in favor of right-hander Chris Stratton, at which point the Pirates gave the game away with a series of mistakes.

Paul DeJong hit a sacrifice fly to right field, scoring one run. Rather than throwing to the cutoff man, Gregory Polanco fired the ball home and allowed the runners to move up a base.

“He’s just got to hit the cutoff man so we can keep the double play in order,” Shelton said.

That mistake proved to be costly when Tyler O’Neill hit a ground ball to sure-handed rookie third baseman Ke'Bryan Hayes. Without an inning-ending double play in order, Hayes attempted to get the runner at the plate. But Hayes didn’t have a good grip on the ball, and his throw sailed wide of Stallings. Goldschmidt scored on Hayes’ first Major League error.

“He’s human,” Shelton said. “He made a mistake. We hadn’t seen him make a mistake.”

The Bucs’ next mistake was, unfortunately, more familiar. Matt Carpenter slapped a grounder to first baseman Josh Bell, who slipped while unleashing a wild, submarine-style throw to second base rather than trying to get the out at home. The ball skipped into shallow left field, and pinch-runner Harrison Bader scampered home.

Bell has put in plenty of work trying to improve his throwing over the years. Last offseason, he dropped his arm angle and said he felt more comfortable with it in Spring Training and Summer Camp. But this was Bell’s third throwing error in only 31 games at first base this season.

“I thought he got caught in between. He thought he was going to throw the ball home, then threw it to second. Once he got there, he was so far down that the ball got away from him,” Shelton said. “On that play right there, we just made the wrong decision on where we should have thrown the ball.”

The inning should have been over by that point. Stratton had recorded one out and induced two grounders that should have accounted for at least one out each.

But the Cardinals continued to capitalize on the Pirates’ many mistakes. Stratton left a fastball over the plate to Dylan Carlson, and the rookie outfielder bashed it out to right field for a game-breaking three-run homer.

“It was a 2-1 game, Reynolds hit the homer, and we didn’t execute. Stratton actually executed,” Shelton said. “He got the two ground balls we were looking for, did his job. And we just didn’t make the plays.”