Nigeria were "underestimated and underappreciated" leading into the Women’s World Cup but have proven their critics wrong, coach Randy Waldrum said ahead of Monday’s crunch Group B fixture against the Republic of Ireland.

Nigeria stunned Australia with a 3-2 victory in their last game and sit top of the pool with four points. Victory over the Irish, who have already been eliminated, would seal their passage into the round of 16.

"We have shown we are a better team than number 40 in the world," Waldrum told reporters.

Having said that, Waldrum knows they have a battle ahead against an Ireland side that narrowly lost their first two games to Australia and Canada and were unfortunate not to get more from those contests.

"It is going to be a very difficult game. People may think I am crazy for saying this, but I think it could be our hardest match. Ireland have been a bit unlucky in the first two matches and could have got a result," he said.

"We are not expecting them to lay down because they are going home already, I am expecting to get the best from them and have been very impressed with their team and their organisation."

One of the stars of the tournament for the Super Falcons has been goalkeeper Chiamaka Nnadozie, who plays for Paris FC and made crucial saves in their first two games, including a penalty in the 0-0 draw with Canada.

"Chiamaka has been a big part of us since I came on board, she is a young player continuing to get better every year," Waldrum said.

"Whenever I do the list for the BBC of top 100 players in the world, she is always there among the goalkeepers and I think she will only get better.

"A lot of people in France know already (how good she is), but now I think the world will see. She made great saves against Australia too and has been a big part of our success."

Waldrum also expressed confidence in leading forward Asisat Oshoala, who has been grappling with niggling injuries for some time.

"She is doing much better, we did the right thing by managing her minutes and we might have to do that again in this match. She will definitely be playing, but we will have to see for how long," the coach said.