The Barcelona star made the difference against Iran and Nigeria after clinching the win with an excellent goal to make it 2-0 against Bosnia-Herzegovina in their opening game.
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The forward says he is desperate to win the tournament, admitting that he is jealous of the Barcelona players who have lifted the trophy.
"Surely I would love to win the World Cup with Argentina," he added. "But not to change the way people view me from outside but because that's our team's objective and to be able to add a new title to my honours list.
"I am really jealous of my Barcelona team-mates who've already won the trophy. No matter how much I ask, they'll never be able to describe that feeling to me and I want to experience it at least once in my career."
The four time Ballon d'Or winner feels he has matured a lot over the last few years and feels the birth of his son, Thiago, has changed him.
"I surely am older and more mature but if I'm in any way different, that is for others to judge. I have matured a lot as a footballer over the last few years," he said.
"I've been through a lot of good and bad things that have made me a better professional and human being.
"Becoming a father makes you see things differently and it has been the biggest change in the recent years for me off the field.
"It's changed me a lot and I am thankful for that."