Promotion expert Steve Bruce has warned his Owls stars to expect an aerial bombardment when they visit Millwall tomorrow night.
Mid-table Wednesday will be searching for a fourth victory in six matches against a Lions side scrapping to retain their Championship status.
But Owls boss Bruce, who led Birmingham City and Hull City to the top-flight on two occasions each, is acutely aware of the threat Millwall will pose at The Den.
He told The Star: "Seventy five per cent of their last 10/12 goals have been from set-pieces. They have got excellent delivery and put it in your box and the big centre half comes and heads it.
"We are under no illusions about what is coming and our defenders will have to be brave and have to put their head there and defend it right."
The Lions are 20th in the standings, just four points above the drop zone. Despite their precarious league position, Bruce is refusing to take Millwall lightly.
"(Lee) Gregory and (Steve) Morison have been around for years and are a handful for any team," said Bruce. "With the surroundings, they roll their sleeves up and you have to down there or that crowd will sort you out.
"If you are genuine or honest, that lot are not going to have you. We are going to have to be exactly the same and match them and hopefully our skills come through."
Bruce, who is likely to be without the services of captain Tom Lees (shin), expects a stern test from Millwall.
He said: "They will be totally different to Reading. They will ask every question of you.
"They are big, brave, honest, get the ball forward quickly and ask your defenders a question. They will put the ball into your box.
"Neil Harris (Millwall manager) has done a remarkable job in what they have achieved. It has not gone so well this year but last year they were handful.
"They are fighting for their lives and it is never easy going to The Den on a Tuesday night that's for sure.
"We have to be ready to roll up our sleeves and have a go. If we don't, we are going to be found out."