Real overcame Rayo 1-0 via a Karim Benzema strike, with Solari pleased about the win, which he discussed after explaining his benching of Isco.
"My interest is in ensuring that all players are well, happy and committed and we all work for that," he said.
"I try not to make mistakes in the formation or the substitutions and I do that because it is part of my job.
"With the way the match went, I brought Dani Ceballos in for Marco [Asensio] because he was tired then Fede [Valverde] for the midfield and Vini came in because he was the only forward on the bench who could replace Benzema.
"We were dominant against Rayo and should have gone in at half-time with a more comfortable lead but when you don't take your chances you will suffer."