A podium in Brazil is "proof" that Pierre Gasly is a talented Formula 1 driver.
But Gasly has been strong since he returned from the senior team to Toro Rosso, and on Sunday he drove through the late crashes at Interlagos to finish second.
"Pierre showed his class here," Marko told France's Canal Plus.
"We know he has talent and today is good proof of that. Nobody saw it coming. It is a fantastic result.
"Everyone is happy for him and we will certainly celebrate," he added.
Max Verstappen - Gasly's former teammate - won the race for Red Bull Racing, making it the first Honda-powered 1-2 for decades.
"I always knew he was a very quick driver," the Dutchman, referring to Gasly, said.
Verstappen will however continue to be paired with Alex Albon in 2020.
"I think this year in the beginning maybe didn't work out the way it should for Pierre, but as you can see, I think he is very strong," he added.
"He has regrouped at Toro Rosso and even before this race he has done a lot of good results. So this is an even bigger motivation," Verstappen added.body check tags ::