MANAUS: Nigeria were the¬†only former Olympic champions to open the men’s tournament by defeating Japan 5-4 in a wide-open, entertaining clash in the Amazonia Arena in Manaus.

The Nigerians shrugged off the jet lag of a late arrival after flight payment problems to stage a quality show which instantly established them s opponents to be feared.

Oghenekaro Etebo, from Portuguese minnows Feirense, scored four of their goals and thus the second hat-trick of the day in a tie which started in freewheeling style with four goals in the first 12 minutes.

The other Group B game in Manaus ended with Colombia and Sweden all-square at 2-2.

The match started conservatively but sprang into life after 17 minutes when Colombia captain Teofilo Gutierrez opened the scoring for Los Cafeteros, converting superbly his first opening on an assist from Miguel Borja.

In the 27th minute Sweden captain Astrit Ajdarevic took a shot from outside the penalty area and Colombia goalkeeper Cristian Bonilla was unable to hold the shot. Mikael Ishak followed up but this time Bonilla parried for a corner.

Just as it appeared Colombia would go into the half with the lead, Ishak scored from 25 yards.

Sweden used the momentum to take the lead in the 62nd minute with a close-range strike from Ajdarevic after a drive from 25m by Palermo midfielder Robin Quaison was only parried by Bonilla.

Twelve minutes later, the game turned again with a penalty after Joakim Nilsson handled after a cross. Dorian Pabon converted the kick.

Colombia almost took the lead again after Pabon swung in a dangerous cross that Sweden has trouble dealing with. They did just enough to clear substitute Harold Preciado’s follow up effort.

Sweden will now face Nigeria in the next round with Colombia taking on Japan in Manaus