Whilst Tsunoda has been getting positive headlines of late, Ricciardo came under intense scrutiny going into the Canadian GP weekend, most notably from 1997 F1 champion Jacques Villeneuve, whose no-filter criticism attracted attention.
When discussing Tsunoda's new deal, Marko could not resist a subtle but brutally honest dig at the Aussie.
"He [Tsunoda] performs consistently well and his personal behaviour has also developed enormously," Marko told Sky Germany.
"He has got his emotions under control. His physical stature is now such that he can complete a race without any problems.
"It was actually quite clear, he was one of our first Japanese juniors and he gradually improved. A little too slow in the beginning but now he is one of the most sought-after drivers on the market."
Later in the interview, Marko added: "He [Tsunoda] is now a complete driver and has proven compared to Ricciardo that he is the faster and better man."
Ricciardo's current contract with RB runs until the end of the 2024 season.