Guardiola backs Man City's Palmer to shine in De Bruyne's absence
De Bruyne is set to be sidelined for up to five months after aggravating a hamstring injury during City's win at Burnley in their Premier League opener last week.
Losing the influential Belgian midfielder is a huge blow to City's hopes of emulating last season's incredible treble-winning campaign.
But Guardiola is hopeful the emerging talent showcased by Palmer already this season can help City cope without their star.
Palmer put City ahead with a superb strike in their Community Shield defeat against Arsenal, then netted the equaliser in Wednesday's UEFA Super Cup final win against Sevilla.
The 21-year-old academy graduate has been linked with a move in search of more regular first-team action, but Guardiola believes he is ready to step up.
"It's not necessary to ask how good he is. You don't need two goals in two finals to define how good he is," Guardiola told reporters on Friday.
"Cole in the previous season arrived in an extraordinary moment, he defined the game in the FA Cup and then had injuries. He couldn't be there."
John Stones has been added to City's injury list ahead of Saturday's match against Newcastle after sustaining a muscular injury in training.
Bernardo Silva remains out through illness, while Ruben Dias could return after missing the Super Cup final.
Following a late night in Athens on Wednesday and the journey home, Guardiola conceded his team face a tough task to prepare for a formidable opponent in Newcastle, who thrashed Aston Villa 5-1 in their opening game.
Having lifted the Premier League, Champions League and FA Cup last season, Guardiola urged City to prove they still have the hunger for more success.
"We need these types of challenges. Everyone wants to beat us and we have difficulties for many reasons, many important injuries, the calendar," Guardiola said.
"It's a challenge again, to see if we can make a step forward. If you want to win you need that.
"In football there are always problems, it's how you overcome that defines if you're a good team or not.
"We accept that this is the challenge. It's why we won: we overcome these kind of positions. We always had less time to recover."
Guardiola has his eyes on winning the Club World Cup in December to "take all the titles" after last season's treble and the Super Cup win.
"The spirit is there," he said. "I know how happy they are. Every day we arrive and see the four trophies in front of us. Wow, how nice is that? How difficult is that? We love it."
