The 32-year-old defender was booked in the 89th minute at the Johan Cruijff ArenA and initially admitted he took the caution on purpose.
His confession led to UEFA opening an investigation to establish whether he had taken the punishment to ensure he would serve any suspension before the quarter-finals, should Madrid advance.
Ramos subsequently back-tracked , saying his intention was to force a foul not a ban, and Solari accepted his captain's explanation.
"Referring to what Sergio said, he has given all the pertinent explanations and he has said clearly that he referred to forcing the foul," Solari told reporters.
"He has also been asked in a tricky way, you [journalists] have your own methods.
"Anyway, he has also explained himself."
Solari was asked about the furore surrounding a gesture made by Gareth Bale towards Atletico Madrid supporters following his goal in the derby.
Bale scored Real's third goal in a 3-1 victory before making an arm gesture towards fans at Estadio Wanda Metropolitano, prompting La Liga to request that the Welshman be punished by the Spanish Football Federation .
It was put to Solari that LaLiga president Javier Tebas has a vendetta against his side, but the Real Madrid boss dismissed the suggestion.
"Persecuted by Tebas? We are persecuted by Atleti and chasing Barca," said Solari
"We would love for everyone to persecute us."
On Bale's celebration, he added: "I think it is just an anecdote. People are reading too much into it."