Red Bull will continue to give Alex Albon "time" to get up to speed alongside Max Verstappen.
As a rookie, Albon was promoted to the energy drink company's senior team mid-last year to replace the struggling Pierre Gasly.
But now the British-born Thai is having the same confidence problem in the same seat, prompting calls for Verstappen to get yet another new teammate.
But Marko, the architect of Red Bull's driver program, says 24-year-old Albon will be given more time.
"As long as we see that he is progressing and his results are getting better, we will give him time," said the Austrian.
"Alex has had a lot of difficulties this season, including the engine problem and the Hamilton incident. As a result, he still lacks self-confidence.
"But he has speed. In the third segment of the race at Silverstone, Alex had good times. But I think it is obvious that he is young and he still lacks experience.
"He needs time to achieve greater stability," Marko added.
As for Red Bull's competitiveness more generally, Dr Marko said Verstappen's win on Sunday shows that the championship is not yet over.
"We have always said that the title has not been decided," he insisted.
"Yes we still have some problems with the car, but the gap to Mercedes is decreasing every week. We just need to start performing stronger in qualifying, because now this is our weak side."
Indeed, Verstappen said at Silverstone that his Honda engine doesn't have "the qualifying mode that Mercedes do".
Marko said: "Many people forget that we almost won the first race of the season and we could have won last week if Lewis had problems with the tyres a little earlier.
"Now Max is in second place overall, so anything is possible. We will only become stronger, not weaker, so I see no reason why we cannot succeed."