Despite a man of the match performance, Dean Henderson acknowledged the Blades were well below-par in Saturday's draw at Rotherham.
Speaking after the 2-2 stalemate at the AESSEAL New York Stadium, the Manchester United loanee was clearly annoyed the Blades didn't manage the game better, having led in both halves.
He remarked: "We got our noses in front and started the game brightly, but we needed to build on that and put Rotherham on the edge.
"We needed to get a grip, we knew what it was going to be like, they work hard for set-pieces and they throw everything at you. They worked us out and wanted it more than us.
"We didn't turn up, when we are at our best teams can't handle us, but we have to keep standards high and be relentless."
Henderson added: "If we want to be successful we've got to be consistently at our best, at the moment we've not been consistent enough and we've got to learn how to see the game.
"It's so frustrating to get caught so late on, especially having been leading twice. It was just sloppy moment after sloppy moment and it's cost us the chance to win three points."