Madrid were set for a dispiriting home draw before the teenager broke the deadlock with an 83rd-minute drive that took a heavy deflection off Kiko Olivas.
The Valladolid defender was credited with an own goal but, having only stepped off the bench 10 minutes earlier, Vinicius won the plaudits for setting the eventual 2-0 victory in motion.
Caretaker boss Solari, who has worked with the attacker for Castilla, is happy to let the external hype grow, even if he is not yet buying into it.
"It's fantastic that people are excited. We can't fight against what goes on outside," Solari said in his post-match news conference.
"Vinicius has his whole career ahead and judgments will be made in time.
"With his virtues and defects, he is one more player in the squad.
"I told him to be bold and to take people on, which is what he knows how to do. I also told him to defend, which he needs to be reminded about."
A largely disappointing Madrid received whistles from the home fans for portions of what seemed likely to be another deflating LaLiga result less than a week on from their Clasico crushing at Barcelona.
Gareth Bale and Sergio Ramos, who scored the hosts' second from the spot, were among the stars jeered, and Solari put the onus on his players to change public opinion.
"They are great pros with a lot of experience," the former Madrid midfielder said.
"Obviously we all need to manage our emotions, and there are difficult moments, and you know what 80,000 people are feeling.
"It's important for this group that have won so much the fans are with them."