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The Vikings gave Carolina quarterback Cam Newton a look that worked for him before.

Safeties Harrison Smith and Andrew Sendejo aligned just inside the numbers, surveying the field from nearly 20 yards back to signal two-deep coverage. So Newton targeted receiver Ted Ginn, who he had found for a 31-yard gain on an earlier go route. This time, cornerback Trae Waynes saw Newton's pass and kept his sprint down the sideline before intercepting the long ball.

The same mistake wasn't made twice, which has been a mantra of a Vikings defense that, through three weeks, stands alone in the NFL as the only group to have not surrendered a 40-yard pass or run. The Vikings might bend, but so far they haven't broken, which is a sign of the discipline and accountability often preached by head coach Mike Zimmer.

"We hope it continues, but that's always the key," Zimmer said. "We gave up the big play right down the sideline on the first drive of the game, which was a bad play."

That play was the 31-yarder to Ginn, when cornerback Xavier Rhodes had a similar assignment to Waynes'. But instead of following Ginn downfield, Rhodes stopped after 5 yards with a dangerous assumption.

"We were in two-deep coverage and [Rhodes] thought he got the guy pushed out of bounds," Zimmer said. "And he didn't get him pushed out."

Newton noticed and immediately targeted Ginn in the open sideline left behind Rhodes and in front of Sendejo at safety. That would serve as a teaching moment, a micro example of the Vikings' in-game defensive adjustments born out of the slightest slip-up or the wrong play call.

After the drive, Zimmer huddled with Rhodes on the sideline to discuss the play that helped set up the Panthers' 48-yard field goal.

"A lot of the times we know we made a mistake, but [Zimmer] sees — I don't know how he does it — but he sees all 11 guys on every play," Smith said. "So he'll get on us and just make sure if it comes back up, we'll take care of it."

Poor communication is often the culprit for breakdowns, whether by busted coverage or leaving a gap open against the run. The Vikings employ a set defensive hierarchy at each level to ensure not one of the 11 links is broken.

Smith calls the shots in the secondary, though when he's up close near the line of scrimmage, he listens to the linebackers who direct traffic to make sure every gap is filled. Along the defensive line, veteran Brian Robison handles stunt or twist calls when the situation arises.

Before Smith's key third-and-1 run stop in Tennessee, when the Vikings trailed 10-3 in the third quarter, he chose the wrong side of the formation for his run blitz. Linebackers Chad Greenway and Anthony Barr corrected him, putting him in position for the critical stop.

"Communicating is a big part," said backup linebacker Emmanuel Lamur, who also played for Zimmer in Cincinnati. "I feel like we're all on the same page, for the most part. That's what makes us a good defense; it's our bond and just communication and us playing for one another."

After facing the likes of Aaron Rodgers and Newton, the Vikings defense has only allowed eight gains of 20 yards or more, tied for second fewest in the league. They have benefited from penalties as Panthers running back Fozzy Whittaker's 56-yard touchdown was called back last week because of an illegal block in the back by Kelvin Benjamin.

However, the Vikings' worst gaffe of the young season also came via a yellow flag when cornerback Terence Newman grabbed Davante Adams early on a deep pass, giving the Packers 40 yards. It was one of eight illegal defensive contact, holding or pass interference calls levied against this secondary in three games.

"Those are things we need to clean up," Smith said. "That's kind of hidden yardage, those penalty plays, but it's just something we always harp on. It's hard to win when you give up explosive plays."