The Magpies were thoroughly beaten by Manchester City 5-0 in the Premier League on Wednesday.
While the Magpies have 43 points and are unlikely to go down, Bruce knows a run of defeats could change that picture.
He wants the players to stay focused until they are mathematically safe.
Bruce told reporters, via the Chronicle: "We've not got our flip flops on. We were down to the bare bones.
"But despite that I expect us to be better and I demand we are better for the remaining games."
He went on to say: "We were down to the bones. It's been difficult.
"When you're missing seven or eight, you're going to find it difficult.
"The manner of it was disappointing. When you come here you've got to be somewhere near your best.
"We knew we were up against it with some of the bodies we had missing but you still expect them to put up a bit more than we showed. It was too easy from the first minute to the last."