Vikings hampered by difficult third-down situations

Third-and-10. That's the average third down-and-distance the Vikings offense faced to keep drives alive during Sunday's 26-9 loss in Pittsburgh. Penalties and shoddy play kept the Vikings and backup quarterback Case Keenum out of manageable situations.

"That's how you lose games," receiver Adam Thielen said. "We talked about it all offseason. When you have a drive going, you cannot take a penalty that puts you in a second-and-20 or third-and-20. It's hard to get out of those situations. We got out of one [Sunday] and I'm not sure how."

An impressive one-handed catch by tight end Kyle Rudolph for 27 yards is how the Vikings converted a third-and-20 in the third quarter, though they failed to move the chains on a third-and-15 later in the drive before punting.

The Vikings were actually successful in manageable third downs — let's call them third-and-6 or shorter — from which they converted four of five attempts. The other 10 third-down attempts? The Vikings were only 1-for-10 on third downs that called for 7 yards or more.

"It's extremely frustrating because we know how well that we can be and we did not prove it [Sunday]," Thielen said.

Running back Dalvin Cook's 26-yard burst was ruled only 25 yards by the officials, meaning the rookie missed out on his first NFL touchdown. Cook was ruled down at the Steelers 1-yard line. From there fullback C.J. Ham scored his first NFL touchdown on the next play.

"I thought I got in," Cook said. "But C.J. [did] all the hard lifting. I'm just glad he got in the end zone."

Defensive end Everson Griffen was a lone standout for the Vikings, sacking quarterback Ben Roethlisberger twice to give him three sacks this season. After Sunday's day games, Griffen was tied for second in the NFL with three sacks through two weeks.

Still, the Vikings defense didn't look like last year's top-five unit. How does Griffen, a team captain, respond after they surrendered 335 yards and 26 points?

"Sense of urgency, man," Griffen said. "We have to go back to the drawing board. Like Coach [Mike] Zimmer said, it's only one game. But you can't let this one game affect this one or the next after that. We just have to bounce back."

The Vikings played what could be their warmest game of the season in Pittsburgh, where kickoff temperature hovered around 80 degrees. The sun heated soggy air holding a forecast 60 to 70 percent humidity.

Some Vikings staff members were tasked with holding up makeshift shades on the sideline, using tarps tied to rectangle frames to shield their benches from the sun.

• Marcus Sherels became the Vikings' career leading punt returner when his 12-yard return in the second quarter moved him ahead of former Vikings receiver Leo Lewis. Sherels now has 1,822 career punt return yards.