Marcus Williams, who whiffed on Stefon Diggs' walk-off TD, explains what happened

There are long shots and then there's what happened on Sunday. With four seconds left and trailing the Saints, 24-23, Vikings quarterback Case Keenum lofted a pass to Stefon Diggs near New Orleans' 35-yard line. Diggs should have been tackled there and the game should have been over. Instead, this happened:

We could watch that 100 more times and we'd have 100 different questions. The one everyone keeps coming back to: What was Saints safety Marcus Williams doing?

And it wasn't like the rookie had no business being on the field at such a critical moment; the second-round pick out of Utah had a solid 2017 season; he started 15 games and had seven pass-breakups and four interceptions. He also graded out as the 12th best safety in the league, according to Pro Football Focus. It's just that on the most consequential play of Williams' career, he whiffed. To his credit, the 21-year-old faced reporters after the game.

"It was just my play to make. The ball was in the air; I didn't go attack it," Williams said, via the New Orleans Advocate. "I've just got to be that guy, go up and get the ball. As the safety back there, you've got to be the eraser. That was my job. The last play of the game, you've got to go do it, and you've got to save the game."

Watching and re-watching Williams on that final play, it's hard to figure out just what he's trying to do. Coach Sean Payton tried to explain.

"It's an outside zone," he said. "We're protecting the sidelines. Anything inside, and you're in pretty good position, the game's over. He jumped and went for the tackle. The call was what we wanted in that situation, the right call."

"Protecting the sidelines" -- that explains why Williams was aiming for Diggs' left side -- he wanted to keep the Vikings receiver in bounds so the clock would continue to run. It doesn't explain why Williams didn't use his arms when trying to tackle Diggs, though it may have been that he wanted to avoid hitting Diggs before the ball arrived.

"I feel like I was a little early, but at that point, I've just got to make the tackle when he comes down," Williams said. "It's just those little things that you see, and you've got to make sure you do all that you can to get him down, regardless of if there were 10 seconds left. I knew the situation. You've just got to make sure you make the play."

Despite the loss and the way it unfolded, Williams has the full support of his teammates.

"He's got to keep his head up. I'm not going to say he's not feeling bad about the play or whatever, but we've got his back," rookie cornerback Marshon Lattimore said. "Marcus is a special player. He can't let that one play, even as big as it was, you can't let that play turn you against him. That goes for the fans and our team."

And it goes for Williams too.

"Just overcome it," Williams said. "You can't let it beat you down. I'm going to take it upon myself to do all I can to never let that happen again, and if it happens again, then I shouldn't be playing."