Antone Exum’s first NFL start was challenging. The Vikings were facing Atlanta’s Julio Jones, the league’s leading receiver, on Sunday as Exum stepped in for injured safety Harrison Smith.

And it wasn’t long before there was added pressure; Andrew Sendejo left the game because of a knee injury, leaving Exum and Robert Blanton as the only active safeties.

“I thought, ‘I don’t care what happens, you’ve got to stay in the game, because we don’t have anyone else that plays the safety position on the sidelines,’ ” Exum joked Monday, a day after the Vikings’ 20-10 victory.

Exum, a second-year player, finished with three tackles, one for a loss, and recovered a fumble. He said he fit in well.

“Everybody just goes out and tries to play for each other,” he said “If you make a mistake, it’s not just about you making a mistake. You’re thinking, ‘Oh man, I could have left the corner out to dry on that one’ … or, ‘I wasn’t in the right gap, and now I put the linebacker in a hard spot’ … so we have a good camaraderie.

‘‘We try to hold each other accountable, so when we mess up, we’re not just playing for ourselves, we’ve playing for the guys beside us.”

Coach Mike Zimmer said Sendejo had an MRI on his left knee Monday, but didn’t reveal the results. With Smith and Sendejo injured, Anthony Harris could be activated from the practice squad before Sunday’s game against Seattle.

Exum, meanwhile, hopes he’s played his way into more regular time in the defensive backfield.

“I do hope that I showed that I can step in and be a starting-caliber safety for this team,” Exum said.

Said Zimmer: “The biggest thing that we did yesterday defensively is we executed the game plan of trying to take care of Julio Jones [five catches, 56 yards]. I thought we did that well and [Exum] was obviously part of it because he was playing in the back end, so I think he did a good job.”

Hand it to him

Anthony Barr has been hampered while playing with a broken hand, but he was a standout Sunday with eight tackles, a sack, two forced fumbles and the prevention of a long gain when he tipped a pass away from Tevin Coleman.

“Anthony basically played two games [vs. Oakland and Green Bay] with one hand,” Zimmer said about his second-year linebacker.

“Last year Anthony was a heck of an athlete that worked real hard at being smart and doing things like we ask him to do. This year Anthony is a lot more vocal, he’s a lot more intense, maybe, on the field. I think that’s a good thing.”

Barr was more critical of himself Monday, but said, “Second year, you should feel more comfortable. Our confidence is high right now and we continue to play well. You can always do better — you strive for greatness.”

Winning ways

The Vikings lead the NFC North at 8-3 and already have one more victory than they did in 2014.

“If you’re not having fun when you’re 8-3, there’s something wrong with you,” defensive end Brian Robison said, but later he added, “at the end of the day, 8-3 only guarantees you one thing. And that’s that you’ll be .500 at the end of the season.”

“We’ve shown we can be pretty dang good, but we’ve also shown when we don’t do that, we can be pretty mediocre.”

The Vikings have four consecutive road wins.

“Like Coach said, it doesn’t matter where the game is played, it’s who plays better that day,” Barr said.

In a slump?

Cornerback Captain Munnerlyn has 10 interceptions in his seven NFL seasons, but returned five of the first seven for touchdowns.

He has three in his two seasons in Minnesota, but no TDs … and was credited with a return of minus-2 yards Sunday after he intercepted Matt Ryan.

“I’m in a slump,” said Munnerlyn, 27. “I was joking with the guys, I had negative yards yesterday. This has to change. Guys are like, ‘You’re getting a little older, and I’m like, ‘No, this has to change soon!’ ”