It was a frustrating evening for Belgium, who saw wave after wave of attack break down before the young substitute found the net at the death.
"[Origi] is in a good place right now," Wilmots said of his goalscorer. "He's 19 years old. It was a bit of a surprise since he was an unknown before I selected him. Now everyone knows who he is.
"It was a hard game because the Russians were expecting us - the players were tired, it was hot, the Russians were already cramping up after 60 minutes. It was not an easy match but I think we deserved to win it."
Belgium round off their Group H campaign with a match against South Korea.