Oghenekaro Etebo's own goal and a Luka Modric penalty gave Croatia a winning World Cup start against Nigeria in a poor Group D match in Kaliningrad.

Etebo, who joined Stoke City from Portuguese club Feirense for £6.35m on Monday, turned Modric's first-half corner into his own net after Ante Rebic and Mario Mandzukic had both got touches.

Modric then converted a 71st-minute penalty - Croatia's first shot on target - after William Troost-Ekong had manhandled Mandzukic at a corner.

Nigeria offered little attacking threat, although Dejan Lovren blocked Alex Iwobi's shot just before half-time, and Odion Ighalo glanced a Brian Idowu cross straight at goalkeeper Danijel Subasic.

Victory takes Croatia top of their group, after Iceland held Argentina 1-1earlier on Saturday.

Modric and Rakitic let down by off-form forwards

At 33, Modric is facing what could well be his final World Cup - along with striker Mandzukic, who is 32, and midfielder Ivan Rakitic, who turned 30 in March.

The Croatia captain won the Champions League for the fourth time in five seasons with Real Madrid in May, but his run up to Russia has hardly been smooth.

He has become unpopular in his homeland over a saga that has seen him charged with perjury - an offence that carries the threat of jail - for retracting his testimony in the tax fraud trial of a senior Croatian football official.

On the pitch, though, he has managed to put that to one side, and provided the class that guided Croatia to an unconvincing victory.

Both he and Rakitic were excellent in their passing, although the lack of movement among the forwards in front of them often thwarted their ambition.

When Croatia did create chances, it was usually their two creative midfielders who were involved. Modric's fine early cross was guided down by Ivan Perisic for Mandzukic to fire over, while Andrej Kramaric's header looped just over the crossbar from a Rakitic assist after half-time.

Rebic, who scored twice as Eintracht Frankfurt beat Bayern Munich to win the German Cup in May, later volleyed a great chance wide from six yards after Rakitic's sublime pass had freed Perisic on the left.

Modric and Rakitic certainly have the ability to unlock the world's best defences - but they will need help from those in front of them when they face better teams than Nigeria.