Goals from Alex Mowatt and Mike Bahre in either half put the home side in control before Keane Lewis-Potter reduced the arrears with his first senior goal, but Barnsley held on to record their first win since the opening day of the season with Conor Chaplin adding a third in stoppage time.
Bowler acknowledged Grant McCann’s side were second best on the day and is targeting a big improvement when the team returns to action against Stoke City at the KCOM Stadium at the weekend.
“I think we just didn’t turn up from the first whistle to the last,” he said.
“It just wasn’t the standards we have set ourselves, we know that, we are all disappointed but we need to go back on Monday and work on it.
“We have mentioned it before, we knew it wasn’t going to be an easy test and we were all raring to go, we just didn’t click. We know the game was going to be tough and we’re not taking any game lightly, it just wasn’t our game today and we have got to really work over the coming week.
“We want to go into every game winning it, it is a setback, but it is a setback that we can’t dwell on, it’s a setback that we can’t let affect us, we have got to go into the Stoke game and try and get three points there.”