The teenage winger struck his first tournament goal within 10 minutes, helping the Europeans race into an early lead before being substituted at half-time
Speaking as a pundit, Rooney was left impressed by his influence, describing the performance as outstanding.
"Do you know what I absolutely love him, he just makes me smile. The enjoyment and fun he plays with," Rooney told the BBC.
"What he does for that Spain team, there’s a lot of young players in that Spain team and he give them that confidence.
“They won the Euros with him as a 16 year old, now he’s matured as a player, which seems crazy to say about an 18-year-old, but he gives every other player on that pitch for Spain a confidence and belief that they can go on and win this World Cup."