The San Antonio Spurs have spent four games building impressive first-quarter leads. The Knicks have spent four games proving those leads don’t tell the whole story.

That’s the strange thing about this series entering Game 5 on Saturday night in San Antonio. The Spurs keep hitting first. The Knicks find a way to rally. The series score says the Knicks lead 3-1. But even with the Knicks one win away from securing a championship, things could’ve easily gone the other way.

The Knicks are minus-47 in first quarters through four Finals games. They’re plus-24 in second quarters, plus-16 in third quarters and plus-15 in fourth quarters. San Antonio has owned the first quarter, then they gradually lose steam.

The Spurs know the pattern. Their problem hasn’t been building leads. It’s been protecting them.

“We have to figure out how to sustain those leads,” De’Aaron Fox said. “We have to figure out how to finish games.”

Stephon Castle saw the same thing after Game 4, like everyone else inside Madison Square Garden. He said the Spurs have had a 10-plus point lead in every game, then stopped playing the same way that built those leads in the first place. The issue, Castle said, started with defense.

“They were able to generate a lot of open shots, whether they made them or missed them, and eventually they started to fall for them,” Castle said. “I feel like that’s how their comeback started.”

The Knicks produced a 180 offensive rating in the second half, or 1.80 points per possession, on plays with Victor Wembanyama defending in isolation, pick-and-roll or closeouts. The Knicks used his drop coverage, over-help and late closeouts against him. It worked beautifully.

Wembanyama can erase shots with ease. He changes spacing just by standing near a ball handler. But the Knicks kept making him choose. Drop, and Jalen Brunson had room to work. Help too far, and the Knicks had release valves. Close late, and the Spurs were chasing from behind.

“Sometimes it feels like if they’re going to spend so much energy trying to put us in a certain position, at the end of the day there is still no mismatch,” Wembanyama said. “It’s not necessarily bad. I don’t think it was a reason why we lost the game.”

The Knicks have continued to find ways to respond to slow starts throughout this series. However, Josh Hart knows they can’t keep relying on it.

“We can’t keep getting into a hole and trying to dig ourselves out of a hole,” Hart said. “We were fortunate to do that last game, actually, all three games, all three of our wins, but we’ve got to do a better job of starting games off.”

DOWN TO THE WIRE

Each of the first four games between the Knicks and Spurs has been within four points in the final minute of regulation. Per the NBA, the last Finals series to begin with four such games was in 1973, when the Knicks faced the Los Angeles Lakers.

The Knicks won Game 2 by one point. They lost Game 3 by four. They won Game 4 by one. The whole series has has been nothing but late-clock possessions, missed box-outs, one extra pass, and Wednesday night, one hand above the crowd.

Knicks head coach Mike Brown has tried to keep his players tied to the next play, not the ultimate prize.

“We’ve been preaching all year it’s about the next possession, the next possession, the next possession,” Brown said.

Brunson traced it to something less complicated.

“Our mentality,” Brunson said. “Our belief and our confidence within each other I think helps us in that aspect. It starts with our mental approach.”

HOLD IT!

New York has found plenty of ways to measure this run. NYC Water found another.

As the Knicks rallied Wednesday night with a game-winning tip, New Yorkers held their No. 1, according to NYC Water. At the final whistle and for the next seven minutes, the city saw a water-use spike equal to 368,697 toilet flushes.

It is a ridiculous detail. New Yorkers didn’t just watch Game 4. They waited. Apartments, bars and living rooms across the city paused at once, everyone too locked into one final stop to leave the screen. This Finals series has altered sleep, routines, flights, bar tabs and, apparently, bathroom timing

NYC Water put it best: “As the Knicks surged, we fought the urge… because we knew the team was on the verge… OF HISTORY!”