Knicks guard Jalen Brunson shoots a layup past Wizards defenders Daniel...

Knicks guard Jalen Brunson shoots a layup past Wizards defenders Daniel Gafford and Corey Kispert during the second half of an NBA game in Washington on Saturday. Credit: AP/Manuel Balce Ceneta

WASHINGTON — If Friday night’s 36-point win in Philadelphia proved that the Knicks are up to the task of competing with the best teams in the NBA, their test Saturday night was a far different one.

Even as they celebrated Friday’s blowout, coach Tom Thibodeau immediately put a damper on it, noting, “In this league, you can’t feel too good about yourself. We got to be right and ready tomorrow night.”

After riding a chartered train down for the second night of a back-to-back set against the Wizards, one of the worst teams in the NBA, the challenge was to keep their level high and not sink to the level of the opposition. And after a dominant first half, the Knicks tested Thibodeau’s patience.

A lead that ballooned to 26 in the first half was chopped to five in the first six minutes of the second half, with an angry Thibodeau calling three timeouts in that span. But finally the wake-up call took hold and the Knicks pulled away for a 121-105 win at Capital One Arena.

The win pushed the Knicks (21-15) to 4-0 since the previous Saturday’s trade for OG Anunoby and, combined with Indiana’s loss to Boston, jumped them all the way to fourth place in the Eastern Conference.

“I think we got it to 26 and then there was their run that got it to 20 [at halftime],” Thibodeau said. “Then they started the third on a run. So then we gave them hope that they could get back into the game, which they did, and I knew that they play hard.

“You guys hear it from me ad nauseam, they — my players — they hear it from me ad nauseam: No lead is safe in this league.”

Up 63-43 at the half, the Knicks saw the Wizards (6-29) score the first six points of the third quarter, prompting a quick timeout by Thibodeau just 1:54 in. Another Washington basket made it an 8-0 start before Anunoby connected on a three, but that hardly stemmed the tide.

Kyle Kuzma’s three-pointer cut the Knicks’ lead to 68-62 and prompted another timeout with 7:57 left in the quarter. Kuzma’s three cut it to 74-69 and Thibodeau angrily called his third timeout in a span of 6:37.

His message in those timeouts? “Can’t repeat it,” Jalen Brunson said. “I can’t. Basically, be better.”

But the Knicks righted the game, riding mostly the scoring of Randle (39 points) and Brunson (33) and again getting a big contribution from Isaiah Hartenstein (19 rebounds, four steals and two blocked shots). They also got a quiet boxscore but a huge effect from Anunoby.

Randle, who shot 1-for-11 Friday, started the game with a corner three-pointer and never really stopped scoring, reaching 39 for the second time in the week. The Knicks took a 34-19 lead at the end of the first quarter, capped by a putback dunk at the buzzer by 6-2 Deuce McBride, who soared over players nearly a foot taller as he raced in along the baseline.

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