Making his full debut, Jesus set up Raheem Sterling, 22, for City's opener in Saturday's fourth-round tie, with 21-year-old Leroy Sane adding a second before Yaya Toure curled in a late free-kick.
Jesus's 43rd-minute assist, a neat spin and piercing pass, was the first return on his £27 million ($33.9 million, 31.7 million euros) move from Palmeiras and his display delighted the City manager.
"He helped us a lot. He's so aggressive, even if he's not a tall guy," Guardiola told his post-match press conference.
"It's the first game, so it's not easy for him to communicate. He doesn't speak English. He will need time. But he makes a lot of movements. The pass for the first goal is outstanding.
"We cannot forget, we play with 21, 20 and 21 (sic) -- three strikers so, so young. It's the future for Man City and all three played good."
Sane made a slow start to his City career following his close-season move from Schalke, but the Germany winger has now scored three goals in his last three appearances.
"He arrived a little bit scared, but it's normal when you arrive in a new country," Guardiola said. "After the game against Arsenal (a 2-1 win on December 18) and his injury, they had four or five days off and he realised he had to make a step forward and he did it.
"Not just in terms of the goal, but his involvement in our game. Not just the actions, but the runs in behind, the quality and fighting.
"It's not easy for a player from another country coming here at 20, 21 years old and playing in a big club. Always he has to learn it's no option but to win, win, win."
Guardiola was also pleased to see captain Vincent Kompany complete 90 minutes on his first outing since sustaining a knee injury during City's 2-1 win at Palace on November 19.
"That is maybe one of the better news tonight," said the City manager. "He was a long time injured and every time he came back he could not finish 90 minutes.
"He was two years injured, but the doctors and the physios and (surgeon) Ramon Cugat made an exceptional job."
Sergio Aguero was absent for City with a leg problem and Guardiola said he would be assessed before Wednesday's Premier League trip to West Ham United.
Guardiola said Toure, who arced a free-kick into the top-left corner in injury time, had been "perfect" since returning to the team in the November win at Selhurst Park, in which he scored twice.
But Palace manager Sam Allardyce took a dimmer view of the Ivorian's contribution, arguing he should have been shown a second yellow card for tripping Jordon Mutch midway through the first half. "They should have been down to 10 men," Allardyce said.
"Mutchy had been booked for much less a couple of minutes before. So the referee has not done his job for me, on the incident that Yaya did there.
"On the consistency of what the referee was doing in the game, it was an absolute certain yellow card. But I'm much more concerned about the goals we are conceding at the moment, rather than the referee."
Allardyce confirmed Palace were close to completing a move for Sunderland left-back Patrick van Aanholt, but played down reports winger Andros Townsend is poised to rejoin Newcastle United.
"I think Van Aanholt is close," he said. "Hopefully he will be involved (at Bournemouth) on Tuesday, January 28.
"I've no idea what the situation is with Andros other than the chairman has told me there has not been any type of bid whatsoever from Newcastle. So that's not even in the back of my mind."