Real Madrid coach Zinedine Zidane said Isco had "made the difference" after he struck twice in the Liga leaders' 3-2 win at Sporting Gijon on Saturday.
Zidane made nine changes to his team, with the game coming between the two Champions League quarterfinal legs against Bayern Munich.
Sporting went ahead through Duje Cop only for Isco to equalise almost immediately, but they led again early in the second half thanks to Mikel Vesga.
Alvaro Morata levelled to pave the way for Isco's winner and Zidane -- whose side host Barcelona next weekend -- told his postmatch news conference: "Isco played a great game and deserved to give the team the victory.
"I am happy with how he played -- he made the difference. I am happy for him. He has the personality to do what he did today."
Isco played as Zidane left out players including Cristiano Ronaldo, Luka Modric and Toni Kroos.
He has been linked with a move away in the summer, but Zidane said: "I feel unfair to all those who do not play.
"That will always happen as I have 24 players who would be starters at any team other than Real Madrid. But that is the difficulty of this job.
"But he is a great player -- he has shown that. Real Madrid is where he belongs."
Zidane admitted his team had not been at their best defensively, saying they were "not focused" at Gijon's second goal.
"That goal is a slip from us," he added. "But we had many chances to score, so in the end it is a deserved result."
It was the sixth time this season that Zidane's team had won with a goal inside the last 10 minutes, but he said: "In football there is no luck -- there is a lot of hard work.
"You must make your own luck. With the team we have, we know we can damage any opponent, and to fight until the end is part of Madrid's DNA."