The 29-year-old former Port Vale, Swindon and Leeds forward joined the Blades from Doncaster on loan until the end of the season on Friday.
But his first appearance the following day saw the Blades suffer a 2-1 loss at Notts County, leaving the club just one point above the League One drop zone.
"It was very disappointing really, it was a tough game," Paynter told the club's official website afterwards.
"I thought for the first 20 minutes we looked very bright and we got an early goal.
"I felt we could have kicked on, but it was disappointing in the end."
Paynter also gave United fans an idea of what he will bring to the table this season.
He added: "I like to get in the box, get some goals and create chances for other people and make it uncomfortable for the centre-halves."