Germany coach Joachim Low hailed Mario Gotze as the "miracle boy" after his extra-time strike sealed a 1-0 win over Argentina in Sunday's World Cup final.

Low also revealed he told Gotze to show the world he was better than Lionel Messi minutes before the substitute came on to score the winner.

Victory gave Germany a fourth World Cup title and first for 24 years.

Gotze, 22, said: "It is an unbelievable feeling. You score that goal and you don't really know what's happening."

Gotze, who began the 2014 Fifa World Cup in Germany's starting line-up, came on as an 88th-minute substitute for Miroslav Klose in Sunday's final.

With seven minutes of extra time remaining, the Bayern Munich midfielder volleyed home with his left foot after controlling Andre Schurrle's left-wing cross on his chest.

"He is the wonder who can play in numerous positions, he is the decider who can come on and make a difference," said Low. "That is what he did."

Gotze, who joined Bayern in a £31.5m deal from Borussia Dortmund last summer, added: "It's indescribable. The dream has become a reality. It is absolutely sensational."

Despite being on the losing side in the final, Messi was named as the tournament's best player.

Coach Alejandro Sabella said the award was "very deserved", adding: "He played a great World Cup to get us where he did."

Germany counterpart Low, meanwhile, said victory in Brazil was the result of a 10-year project.

Germany were knocked out at the group stage of Euro 2004 without winning a game but have since reached three semi-finals and two finals at five major championships.

Before Sunday they had not won a tournament since tasting success in the 1996 European Championships in England.

"We've made constant progress and believed in the project," said the 54-year-old Low, who became coach in 2006 after stepping up from his role as assistant to Jurgen Klinsmann.

"If any group deserves it, it's this team."