When you don't work hard enough or simply give up on the big ticket effort plays.

Or when you clock off momentarily and let your concentration lapse at the crucial time.

Call it desire, or effort or desperation. Define it how you like but in the moments that really mattered on Saturday against Penrith at McDonald Jones Stadium, it was the Panthers who found that something extra.

And it proved the difference between winning and losing in a hard-fought two point game.

Knights coach Nathan Brown summed up his side's 16-14 defeat, claiming Penrith "beat us to the punch".

"I just thought there were a couple of key moments and they came up with those big plays and we didn't come up with them," Brown said.

"Were they that much better than us? No, but they got some better attacking kicks in and gave their blokes some better shots at it. We probably weren't as good there but there wasn't a huge amount in the game.

"I just thought there were a couple of times there where if we worked a touch harder, or if individuals worked a touch harder, we might be sitting here with a smile on our face."

The key moments Brown referred to was the try to Panthers forward Frank Winterstein five minutes from halftime that came as Knights teammates Connor Watson and Shaun Kenny-Dowall willed a Nathan Cleary kick to go dead, only for a desperate Malakai Watene-Zelezniak to climb over the top of them to bat the ball back for his teammate to pounce.

To blame only Watson and Kenny-Dowall would be letting their teammates nearby, who had dropped off and failed to react quickly enough, off the hook. 

That try gave the Panthers a 10-8 halftime advantage. But just as crucial was James Maloney's remarkable effort in cover defence to reef the ball free of Edrick Lee over the try-line with 11 minutes left when the Knights winger was going to score for all money.

There were other telling plays. Watson was correctly denied an early try with a defender obstructed who wouldn't have stopped him anyway while Kalyn Ponga failed to get a hand on a Mitchell Pearce dink into the in-goal in the second half with suggestions he may have been interfered with as he tried to ground the ball.

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The positives for the Knights were the performances of bench forwards Mitch Barnett and Aidan Guerra, who both made big impacts. But it was the Panthers who deserved most of the plaudits.

Generally, Maloney controlled things beautifully and his side ran with more vigor and got off their line in defence with more intent.

The Knights didn't lie down and were given a late sniff after a solo effort from Barnett but overall, they paid the price for being out-enthused when it mattered. 

That's not something that should happen at home.