The Swans have won one of their last six games in the league and are just three points above the relegation zone in the table.
"We've been looking over our shoulders for a while now," Monk told the club's official website. "It's a serious situation, we know that, and we need to get some points on the board as soon as possible.
"It's crunch time now and I want us to get wins and finish with as many as possible. Newcastle is a chance to get three points and that's what we'll be aiming for.
"We've done well there in recent years. I played there the last time we won, and we need another performance on Saturday. It's going to be a difficult game for us, and I expect a reaction from them. Their fans will be demanding a performance so we're expecting a tough game."
Swansea visit Newcastle United in the Premier League on Saturday afternoon.