Nigeria's Golden Eaglets were made to work extremely hard for their opening day victory against a Hungary side that caused problems.
The Nigerian team went into the game knowing that tournament history favoured them for a win, but they were stunned by the Europeans from early in the game.
With just three minutes gone at the Estádio Olímpico, Goiânia, Brazil, Gyorgy Komaromi opened scoring for Hungary after a defensive lapse.
But the lead was cut short when Samson Tijani converted a 20th-minute penalty after Wisdom Ubani was brought down in the penalty area.
But just before the half hour-mark, Hungary were back in the lead again. Samuel Major took advantage of another defensive error and drove home a goal.
The first half ended with the Europeans defending their slim advantage doggedly and they deservedly took the lead into the dressing room at half time.
A Nigerian U-17 team had never lost the opening game of a FIFA World Cup and Manu Garba's boys weren't going to be the first.
They resumed the second 45 minutes with more hunger for an equaliser but their opponent kept frustrating their efforts.
It took the introduction of Akinkunmi Amoo who replaced Monsuru Opeyemi for the game to spark into life for the West Africans.
Eleven minutes from time, the Eaglets got their equalizer. Usman Ibrahim rose highest in the box to head home Ibrahim Said's corner kick.
With the game levelled, the Nigerian boys could smell blood and they went all out for it. Adeniyi Timilehin completed the turnaround for Nigeria before fantastic captain, Tijani, made it four for the Golden Eaglets from the free-kick spot.
The victory put Nigeria top of Group B ahead of their next game against Ecuador on Tuesday. The South Americans also won their opening game 2-1 against New Zealand.