When did they know it was going to be their night?

When did you know?

Was it when Tyreke Evans, showing the hustle and grit that has carried him through the season crashed into the support going in for a layup, got up slowly and then took a pick and roll from Omer Asik for the layup?

Or was it when Evans stole the ball from Manu Ginobili and fed to Anthony Davis at midcourt who then seemingly needed only three strides to reach the basket for a monstrous dunk?

Or was it when Davis brought the ball across midcourt after a Norris Cole and this time zipped a pass to Ryan Anderson in the corner who was money on the three-pointer?

Take your pick of that and 108 points worth of difference-making plays Wednesday.

On a night when the Pelicans absolutely, positively had to be at their best — they were.

Their playoff-clinching 108-103 victory against the defending NBA champion San Antonio Spurs was a rousing display of effort by a team written off more than once this season as just not quite ready to be considered in the upper echelon of the Western Division.

At midseason, they were 20-21 following a Martin Luther King Day loss to the dismal New York Knicks and there were whispers that Monty Williams wouldn’t survive the week.

Just three weeks ago, a 95-93 homecourt loss to Houston — the Pels’ fourth in a row — left them 3½ games behind Oklahoma City with 11 games to play.

Computers put their chances of making the playoffs at less than 5 percent. Most hearts and minds had them lower than that.

But the Kevin Durant-less Thunder finally started coming back to Earth, and with four games left they were dead even, with the Pels holding the all-important tie-breaker which was in their favor thanks to a 3-1 edge over OKC this season.

Still it came down to having to beat the team which not only has been the benchmark for success in the league for the past two decades, but also had plenty of motivation for winning Wednesday.

Just not as much as the Pels, who celebrated as if they had won the title themselves — including dropping confetti — along with the rest of the red-clad Smoothie King Center crowd after it was over.

The Pelicans are probably not ready for that leap. You just don’t do that in the NBA.

And a first-round series against top-seeded Golden State most likely will demonstrate that.

But on this night, it didn’t matter.

It was a time to mark the next big step in the progression of a franchise whose last trip to the playoffs came when they were still called the Hornets, the building was still called the New Orleans Arena and the NBA was running things because there was no owner.

And don’t forget that Davis was still a senior in high school.

Yep, it’s been a while, although four years shouldn’t seem that long.

Know what’s longer?

Those final six minutes after Davis made two free throws to put his team up 94-83.

The Spurs chipped away and chipped away, eventually getting it down to three points on a Patty Mills 3-pointer that made it 104-101 with 9.5 seconds left.

In a city that’s seen the Saints squander far too many seemingly safe victories, it was time to hold your breath.

But Jrue Holiday, in only his third game back after missing 41 in a row and seemingly being shelved for the duration just a week ago, hit two free throws and with a two-point lead the victory was assured.

That the game was tight at the end should have been no surprise.

How many teams other than the Spurs can withstand a 21-1 run like the Pels and come back to make it close in a situation where saving their energy for the playoffs might have been advisable?

Nope. Spurs Coach Greg Popovich may have been a mentor and more to Williams, but San Antonio came to win.

And the Pels also got no help from the hapless Minnesota Timberwolves who didn’t put up much of a fight against OKC, which was holding out hope that the Pels couldn’t come through.

But they were wrong.

Just like the oddsmakers who made San Antonio a 3-point favorite Wednesday plus a lot of other folks.

But the Pels knew better.

“Three weeks ago, Monty told us, ‘I’ve been around too long,’ ” Davis said. “Anything can happen.”

And it did.

But you just knew it would turn out this way.

Didn’t you?