The coach, 45, believes that the former Manchester United star proved to be the difference in the clash with los Blancos on Wednesday
The 28-year-old fired the Blancos into a 2-0 lead in the Champions League tie, before a further double from Angel Di Maria within the final 20 minutes capped another free-scoring performance in Europe's elite competition.
Solbakken believes that errors were made by his team but took nothing away from the former Manchester United forward's performance, who he thinks was the crucial factor in the clash at the Santiago Bernabeu.
"Cristiano's first goal could have been avoided. It was our mistake," the 45-year-old told reporters. "But I cannot criticise us for the second goal - he came charging into the area and scored. He was the match-winner.
"He was quiet for a while, but then he made the difference in the decisive moments."
Carlo Ancelotti's men, who coasted to a 6-1 victory over Galatasaray in gameweek one, remain at the summit of Group B, four points clear of second-placed Juventus and five points adrift of Copenhagen and Roberto Mancini's men.