Quarterback Kirk Cousins was sacked twice as the Redskins went three-and-out on their first three drives before getting going. (John McDonnell/The Washington Post)

Running the football has never been Jay Gruden’s calling card — not as an offensive coordinator in Cincinnati and not as a head coach in Washington.

But if there was a lesson in the sketchy body of work staged by the Redskins’ starting offense this preseason, it’s that running the ball is the team’s best play. And Gruden would be wise to heed it, at least until quarterback Kirk Cousins regains his timing, develops a rapport with a largely remade receiving corps and adapts to an offensive line that has yet to replicate the stout protection it provided the past two seasons.

Sunday’s preseason game against the Cincinnati Bengals at FedEx Field was the final dress rehearsal for Gruden’s starters, and it was unsettling in its futility early on, before backup Colt McCoy engineered a 23-17 comeback that improved the Redskins’ preseason mark to 1-2.

For the third time in as many games, the Redskins’ first team started slowly on both sides of the ball. Through its first three drives, the offense failed to produce a first down and netted one yard. The running game sputtered, and Cousins was sacked twice, more than negating the 11 yards he had gained on two completions.

[Biggest takeaways from the Redskins’ win over the Bengals]

The fourth offensive series ended on an interception, Cousins’s first this preseason. He was late with the throw, intended for running back Chris Thompson, which enabled Bengals linebacker Vontaze Burfict to grab the ball instead and run it back 62 yards, deflecting Cousins’s last-gasp shoulder tackle to scoot into the end zone for a touchdown that extended the Bengals’ lead to 14-3.

Before that, wide receiver Terrelle Pryor Sr., on whom so much depends after the Redskins let deep threat DeSean Jackson depart via free agency, dropped what should have been an easy catch in the open field. And the Redskins’ defense appeared to sleepwalk through its opening series, allowing Bengals quarterback Andy Dalton to lead his team 87 yards in 15 plays on a touchdown drive that gobbled up nearly nine minutes.

All told, it was enough to coax boos from a crowd of 52,016 that surely knew preseason games don’t count yet was disgusted enough to make its sentiments known.

The drive fans had paid to see didn’t come until midway through the second quarter. And it didn’t happen until second-year running back Rob Kelley bored up the middle on a well-blocked play for a 21-yard gain. Kelley capped the 10-play drive with a one-yard touchdown. Credit Pryor, too, who atoned for his earlier drop with a 17-yard gain on a third-and-long despite getting hammered by Bengals defensive backs.

“After Rob had a few runs, he got back in his groove again,” Thompson said. “I think that’s what we need going into the regular season. We’ve got to run the ball good in order to be successful. We can’t have Kirk throwing the ball 40, 45 times a game.”

Left tackle Trent Williams said the offensive line’s goal at the outset had been to get the backs 100 rushing yards Sunday before bowing out. They fell short, with Kelley accounting for 57 of the first-team’s 77 rushing yards. But in Williams’s view, the progress was encouraging.

[Vontaze Burfict dances in the stands after his interception for a touchdown]

Not satisfied with the production, Gruden brought his starting offense back to open the third quarter, but it fizzled on a three-and-out. With it, the Redskins’ offense concluded its preseason with weighty questions at nearly every position that are bound to trigger a raft of second-guessing: Was Gruden’s training camp too easy? Can wide receiver Josh Doctson, who didn’t play Sunday with soreness in his leg, stay healthy long enough to vindicate his first-round selection? And how good can Cousins be (10 for 19 for 109 yards, no touchdowns, one interception Sunday) if he’s not confident in his protection?

Cousins was under fire much of the early going, though Gruden noted that he held on to the ball too long in a few cases. When he let it fly, it was clear he’s most comfortable with his familiar targets: Thompson and wide receiver Jamison Crowder, small athletes with huge competitive hearts, and tight end Jordan Reed, who made his preseason debut after idling the past month with a sprained big toe.

The Cousins-Pryor relationship that looked so promising during training camp hasn’t yet translated to game-day situations. Pryor was targeted four times Sunday but caught just one ball.

More troubling was the absence of Doctson. The 2016 first-round pick missed all but the first two games of his rookie season with Achilles’ ailments. He looked impressive in camp until he was sidelined by a strained hamstring. After missing the preseason opener, Doctson made his debut last week against Green Bay and made one catch. And that’s how he will conclude his 2017 preseason: with one catch.

The offensive line remains a work in progress. Rookie Chase Roullier started in place of center Spencer Long, who underwent knee surgery last week, and appeared to hold up well. It’s unclear whether Long will be healed for Week 1.

As for the slow starts, Gruden said: “I think the guys will come out with a little bit more energy, more urgency hopefully come Philadelphia.”