Brazil star Neymar says the challenge that ended his World Cup was unacceptable and could have left him in a wheelchair.

The 22-year-old fractured a vertebra in his spine when kneed in the back by Colombia's Juan Zuniga during Brazil's 2-1 quarter-final win.

In an emotional news conference, a tearful Neymar says while it was "not a normal challenge" by Zuniga, he "feels blessed" that it was not more serious.