Brazilian midfielder Oscar credits the skills picked up playing indoor football for his virtuoso World Cup debut.

The Chelsea star played superbly in Brazil's 3-1 win against Croatia, helping to create two goals before adding an opportunistic late strike.

The 22-year-old said his inspirational performance at Sao Paulo's Corinthians Arena had its origins in 'futsal', the increasingly popular brand of indoor football which emphasises skill.

The futsal factor could be seen in Oscar's delightful toe-poked finish for Brazil's final goal.

"I can't explain it. I just shot and scored," Oscar said when asked about his strike.

"It was like something you might do in futsal. A lot of the squad started out playing futsal.

"When you get the chance you shoot, but I was just lucky that the ball went in."

The goal and the performance marked the coming of age of the slightly-built playmaker, just a week after he became a father for the first time following the birth of his daughter Julia.

Oscar says fatherhood has inspired him to perform.

"Becoming a father gave me extra strength so close to the opening game," he said.

In the run-up to the game, some observers had called for Oscar -- who made his international debut at the age of 20 in 2011 after breaking through with Sao Paulo and then Internacional of Porto Alegre -- to be replaced.

But coach Luiz Felipe Scolari has given Oscar's critics, who called for him to be replaced by Chelsea team-mate Willian, short shrift.

A look at Scolari's team selections since he returned to the helm of the Selecao at the end of 2012 confirms as much.

Only Neymar has played more games for Brazil over the last 18 months and only Neymar and Fred have scored more goals than Oscar, who has six in 20 matches in that time.

"'Felipao' has shown faith in me for a long time," admits Oscar, before adding: "We have a great team. Nobody is an automatic starter. There is so much competition. Willian, Ramires and Hernanes have shown what they can do. We need to prove ourselves in every game."

Oscar certainly did that against Croatia, running more than most of his colleagues and winning the ball back more than anyone else.

His outstanding display came from a starting position on the right wing, in contrast to last year's Confederations Cup run, when he appeared more through the middle.

"I don't have one position where I feel good. I just like playing, winning the ball back, starting attacks. I don't care if I play right, left, through the middle, as a midfielder or as an attacker," he said.