All the Warriors had to do was win a game they were favored to win by double-digits.

They simply had to beat a team that was not served by winning. The Dubs were on their home floor. They were coming off a half-game in Phoenix the night before — their opponent played a down-to-the-wire contest in Los Angeles at the same time.

The Warriors just had to hold double-digit leads from both the first and second halves.

Of course, we know the Warriors didn’t do that, because that would have been the easy and prudent thing to do. Still, 80 games into this season, these Warriors seem incapable of making things easy on themselves. Amid a slew of rivals, this team remains its own worst enemy.

Their disastrous second and fourth quarters lifted the San Antonio Spurs to a 114-111 win — Harrison Barnes nailed a 3-pointer at the buzzer — and dropped the Warriors out of the top six seeds in the Western Conference standings with two games to play.

The season was not lost on Wednesday night, but it was certainly extended. Instead of being able to go into the weekend feeling confident they’d have next week off from play, the Dubs will instead have to win both of their remaining games — Friday in Portland, Sunday against the Clippers at home — to avoid the play-in tournament.

And even that might not be enough. The Warriors no longer control their own destiny for one of those true playoff spots.

“A good team takes care of business the next two and goes from there. We have to prove we’re a good team,” Steph Curry said after the game.

Indeed, they do.

In recent weeks, while we — and I put myself directly in the line of culpability here — have prognosticated home-court advantage, multiple rounds of victory, and perhaps even title contention, we’ve also overlooked a few key factors.

Like how dependent the Warriors are on rookie center Quinten Post.

Yes, dependent.

Post was inserted into the lineup because his shooting mitigated Jimmy Butler and Draymond Green’s inside-the-arc play. The Warriors try to get away with two non-shooters on the floor. Without Post, they were back to playing three like it was 2008 … or last season.

Of course, Post has defensive issues, which is why he wasn’t in the rotation to start the season. But being seven feet tall and a shooter overrides all of that for now. We’ll see how long that lasts if the Warriors are lucky enough to play much longer.

There was also how Brandin Podziemski’s offensive surge, while necessary, was never likely to become his new norm. Not this season, at least.

Podziemski is a wonderful, winning player, but his nearly 22-point-per-game average in the seven prior contests to Wednesday’s was built on incendiary 3-point shooting. More than half of Podz’ shots were from beyond the arc, and nearly 60 percent of them went in.

He was always going to regress to the mean.

Or — and this is the big one here — how this team is led by three stars with a combined age of 107. You can’t tell me Draymond Green wasn’t gassed on Wednesday. He can be a bit loose with the ball, but he was downright aimless against the Spurs in crunch time.

In the last few games, we’ve seen Curry score 3 points in one and Green play with zero awareness in crunch time in another. The Warriors look like geniuses for letting Butler hang in the wind — suspended by the Heat — for as long as they did. His legs should be fresh for at least these final two games.

No one was suggesting that the Warriors were a flawless team, even if expectations were accelerating so fast that we overlooked this team’s faults.

But it didn’t take much for this team to reach a point where those flaws are now on full display, and a situation where, flaws and all, nothing but winning will do.