The Brazilian set up Callum Wilson for the first in the 88th minute and added his side’s second 99 seconds later.
It was his first Premier League goal of the season and a third in the top flight since joining Newcastle for a club-record £40m in July last year.
“Sometimes you need time – it doesn’t matter about the price tag,” said Bruce.
“In Joe’s case, the price tag and number nine shirt meant he struggled at times.
“But the kid wants to do well. He had a lot of opportunities tonight but we are starting to see him now with his strength.”
The former Hoffenheim striker had gone 16 Premier League games without a goal or assist, before grabbing one of each in Friday’s victory, which moved Newcastle up to 10th in the table.
“There is no disputing that Joelinton has found it difficult,” added Bruce. “But I’ve said many times that some take a little more time than others. We’re delighted he’s scored a goal.”
Palace had looked more likely to break the deadlock and the visitors had goalkeeper Karl Darlow to thank for keeping them in the game.
He saved well from substitute Christian Benteke’s powerful header having earlier made a smart stop to keep out Jeffrey Schlupp’s angled left-footed effort, while Patrick van Aanholt fizzed a strike wide.
The result moves Newcastle up to 10th in the table, while Palace slip to 13th.
Joelinton’s hard work pays off
Bruce’s Newcastle side had failed to score in their previous two outings but looked far more expansive to start within south London on Friday.
Joelinton managed four shots in the opening 20 minutes, as many as he had previously had in any game this season, and the best chance of the half fell to him before the break.
Sloppy defending by the hosts allowed the Brazilian to engineer a low effort on goal, but it was easily gathered by Guaita and the Magpies went in at the break having failed to score in the first half of 20 of their past 26 Premier League matches.
Newcastle looked set to make it three games in a row without a goal as they were increasingly pegged back, but the breakthrough did eventually come as Joelinton combined superbly with fellow forward Wilson.
His pass sent England forward through on goal and Wilson slid an effort beneath Palace goalkeeper Vicente Guaita to open the scoring with two minutes remaining.
The 24-year-old then got the goal his hard work deserved moments later, beating Guaita with a left-footed effort after Wilson returned the favour with an assist.