De Vries has had a rough start to his F1 career, struggling to match team-mate Yuki Tsunoda in his first five F1 races after being signed to replace Pierre Gasly.
The 27-year-old Dutchman has suffered a spate of costly crashes while also failing to match the Japanese driver's pace both in qualifying and in races.
In Monaco De Vries reached Q2 for the second consecutive time as he cut the deficit to Tsunoda to less than two tenths.
On Sunday he put in a measured drive to 12th, re-gaining a place he lost to Valtteri Bottas when Tsunoda's brake issues dropped him down to 15th.
It followed a Miami Grand Prix weekend during which De Vries outqualified Tsunoda for the first time.
Red Bull's Marko said he was much more satisfied with how his latest signing performed on a tricky Monaco weekend.
"This was by far his best weekend for AlphaTauri," Marko told Autosport. "Nyck was much closer to Yuki than before. This is what I want to see from him.
"Yuki was also really good until the brake problems came again. This is something that has to be solved by the team, they have brake problems so often."
Source: Autosport