LOS ANGELES — This Western Conference semifinals series took a sudden and intense turn Monday, pushed both teams to the limit, put the stars on the spot, saw the score tighten in the moment of truth, and a hard truth emerged:

The Warriors are reeling.

The Lakers are feeling it.

The series is 3-1 in favor of L.A. and the best-of-seven has officially entered red alert territory, because there are three elimination games left … if it goes three. Golden State had better hope so, or the defending champions are done and the resurgent Lakers will extend their remarkable turnaround deep into May.

Once again, the Lakers and Warriors engaged in adjustment-making, and the best was the Lakers’ defense. They made it tough on Stephen Curry and Klay Thompson to get clean looks (they went a combined 6-for-23 on 3-pointers in Game 4) and this was evident for Thompson all game and Curry on Golden State’s final possession, with the Warriors down a point.

Isolated on Anthony Davis, Curry missed an 18-footer, got another chance when Draymond Green grabbed the offensive rebound, and then missed again over Davis when he put up a 29-foot 3-pointer.

And the most unexpected adjustment? The Lakers went to a forgotten player off the bench, threw him into an inferno, and now that player has a new twist on his name today:

Lonnie Walker The Fourth (Quarter).

Here are five takeaways from the Lakers’ 104-101 victory as the series shifts to San Francisco for Game 5 on Wednesday (10 p.m. ET, TNT):

1. Walker’s big moment

Lonnie Walker IV outscored Curry, Thompson, Davis and LeBron James in the fourth quarter. In a close fourth quarter. Of a playoff game. Just like everyone predicted. This from someone who didn’t even touch the court in Game 1, a player whose fourth-quarter minutes previously in this series could be counted on one hand. When he checked into Game 4, he immediately dropped a 3-pointer. Normally that would put the Warriors on guard, but their defensive attention stayed with James and Davis — why would it not?

Goodnight, Lakers fam. pic.twitter.com/GQqohbNJA3

— Los Angeles Lakers (@Lakers) May 9, 2023

Walker stayed aggressive and took nine shots in the quarter — more than James and Davis combined (five). When the ball rotated his way, he seized advantage. He played the entire quarter because, by then, there was no need for the Lakers to sub him out, he was that crucial to the victory. He said: “I’ve got a lot of confidence in myself. I knew what I could do if the opportunity came my way.” The fifth year swingman signed as a free agent last summer, began the season as a starter, then fell through the cracks after the Lakers shuffled the deck. Now he just had the fourth quarter of his professional life.

In almost every game in these playoffs, the Lakers have received something big from a player not named LeBron or AD: D’Angelo Russell, Rui Hachimura, Austin Reaves, etc. Now, add Walker to that list, too.

2. Mayday for Klay

To say it was a rough night for Thompson was putting it mildly. He was a non-factor and, for much of the game, left Curry to splash alone. This was due to two reasons: the Lakers prevented him from many clean looks and Thompson simply missed shots. For a stretch of the second half he wasn’t even involved in the flow.

Incredibly, Thompson took only 11 shots in a playoff game, and just three in a close fourth quarter — one of them a forced 3-pointer from nearly 30 feet that missed badly, followed by another from nearly the same distance. His slumped body language said it all as he finished with nine points. What a change of fortune for Thompson, who had 55 points the first two games and hasn’t impacted the series since. The Warriors must find another way to spring him free off screens that the Lakers have figured out, or their season is all but finished.

3. Is Poole finished?

This is a question not only for this series, but his future with the Warriors. The latter part will be addressed this summer, before he begins a four-year, $128 million extension. As for this series? Maybe a clue was provided Monday when Poole was benched after a scoreless night.

At this rate, he’s unplayable. The mistakes, bad shots and shaky defense are multiplying and hurting the Warriors. Even worse? With Poole — one of the Warriors’ main offensive weapons — on the bench (he played 10 minutes total and just two in the second half), the Warriors had to go with Moses Moody (who’s not respected by the Lakers for his scoring) down the stretch. With Thompson locked in a slump, the Warriors desperately needed better from Poole. With nothing from Poole and Thompson, it placed enormous pressure on Curry to carry the load. The Lakers sensed this and threw their strategy toward trapping Curry. Poole is shooting 2-for-13 the last two games and hasn’t made a 3-pointer since the first game of the series.

4. Davis dominates Green (again)

The notion that Draymond Green is getting the best of Davis since he began guarding him in Game 2 has officially fizzled.

Davis has now produced big on back-to-back games while Green’s defensive impact is shrinking. He had 23 points, 15 rebounds and three steals in Game 4, two nights after he posted 25 points, 13 rebounds and five blocks.

What’s really hurting the Warriors is when Davis gets touches in the paint, then elevates for mid-range hooks and jumpers. He hasn’t taken a 3-pointer since Game 1 and hasn’t made one all series … and is still causing damage (Game 2 aside). What’s more, when the Warriors are forced to double, someone is left open — it was Walker this time — as the Lakers are making Golden State pay for the respect they give Davis.

5. LeBron Or Curry?

This series began with the automatic billboard grabber involving two of this generation’s greatest players. Therefore, what’s the tally so far? Not necessarily the record — obviously James’ team is up 3-1 — but on performance?

That also belongs to LeBron, slightly, who has played relatively well in every game, even the blowout loss. Meanwhile, Curry was the only impact player for the Warriors in Game 4 — he had a triple-double (30 points, 10 rebounds, 14 assists) and led his team in those categories — but wasn’t his typically efficient self once again. He finally cracked 30 points in this series, yet worked extremely hard just to get his looks at the rim (he shot 12-for-30). James doesn’t seem gassed by the pace of this series, where there’s been a game every other night. In fact, he is getting to the arena almost five hours early to warm up. Evidently it’s working: he’s producing when necessary and is one win away from sending Curry home.

27 PTS, 9 REB, 6 AST in the Game 4 win!

LeBron and the Lakers can advance to the Western Conference Finals with a Game 5 win Wednesday, 10 PM ET on TNT.#PhantomCam pic.twitter.com/uQXQFFAnx9

— NBA (@NBA) May 9, 2023

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