"We know Mexico very well, they are an outstanding team and will be very difficult opponents on Monday," he said.
"They nearly came through their group with a perfect record and that shows what a good team they are.
"But it has already been a very surprising tournament and I'm sure there will be a few
more surprises along the way.
"We now have 72 hours to get our players mentally and physically ready to play against a very difficult team."
"It has already been a very surprising tournament and I'm sure there will be a few more surprises along the way."
Arena paid credit to Poland for their performance against his side, who collected four points in group D from a surprise 3-2 win over Portugal and a 1-1 draw with South
"I was disappointed by the result but I must give the Polish team credit," he said.
"Our guys never quit and played well for parts of the game."