The 20-year-old has impressed in Spain and Europe with a string of scintillating performances this season, and earlier this month Goal.com exclusively revealed that Premier League champions Manchester City are willing to meet his £17.5 million release clause in January.
He was selected by a panel of 30 journalists working for the most influential publications, with representatives from 20 nations.
Isco becomes the 10th player to receive the award after an initial 40 players were selected from the European football scene.
"I'm overjoyed. It is a wonderful thing. I see the past winners and it almost makes me shiver, names of the highest prestige, like Messi," he told reporters.
"This Golden Boy [award] will be an incentive for me to become a real star of international football, like those who have gone before me."
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"I hope so. I think that now in three years we have won and I think we can continue to win in the future.
"For us, it is important to win a trophy every year. If we continue to do it this, it will be good. I think we need to win more. More.
"I always win. I think one season with Lazio we didn't win anything, but our premier target was to take the Champions League place and we got into the Champions League."Despite this, Mancini admits winning the Premier League title this season will be an even harder challenge than it was last term
"I think now our target will be to win the second title because to win two titles in a row will be very important," he said.
"It is easy to arrive on top but it will be more difficult to stay there for a long time. This is the big challenge for us.
"United have confidence because they are used to winning for 20 years. Their mentality is stronger than our mentality in this moment.
"But as a team our quality is the same level as theirs in this moment. We showed this in the derby. Although we lost 3-2, we showed we were better in that game."