Jones is under increasing pressure to mastermind his side's first win of the season following successive league defeats and their Capital One Cup exit at the hands of South Yorkshire rivals Rotherham, but McDermott is reading nothing into the Owls' early results.
"It's nonsense, complete nonsense," McDermott said. "He's a really good manager and a good man and he's done a good job for Sheffield Wednesday.
"It's ludicrous that you lose a game and you're under pressure and lose two games and it's a disaster.
"Results are massive, we know that, but your philosophy can't be dictated to by one result.
"You can lose a couple of games, that's football. They were unfortunate to lose the game at QPR, they played well and were 1-0 up and last week against Burnley they got back to 2-1 and were pressing.
"They will be determined to get the right result this time, rest assured."
McDermott has happy memories of his only previous derby clash against Wednesday as it ended in a 2-1 win for Leeds in his first game in charge of the club in April and effectively guaranteed they could not be relegated.
"Well I've been involved in a lot of big games, play-off finals, FA Cup games and games that have won us the league and that was right up there," McDermott said.
"I didn't want to say it at the time, I tried to underplay the game as best as I could, but I felt if we had lost that game we might have been in a bit of trouble. It was important we got the right result."