Simon Grayson admits he needs more quality in the final days of the transfer window, but said his current team must improve in terms of their work ethic.
Grayson only made two substitutions as his side failed to fight their way back into the game.
He expects the final few days to be 'hard work' but remains hopeful of making changes to the squad.
He said: "I think overall today it showed we need to be better as a group, not just in terms of individuals. You can’t just blame the whole back four for the goals because its too easy with what’s in front of them sometimes. When we went to Norwich we worked for the shape and the team and we won, today we didn’t work hard enough as a group and that’s sad.
"We know that after the window shuts we’ve got players coming back. Over the next few days its probably going to be a lot of hard work. You never know, nothing might happen. Obviously we want to bring players in and others going out will help us get even more in. We'll have to see where we go with it all, which is what we've been saying for the last few weeks.
"We’ve said that there’s going to be disappointments along the way but [we have to] at least give our all. We’ve taken one step forward over the last two weeks and taken two back today. There’s a lot of work still to be done, I only want players here who are committed to it and we have to work hard to get it right.
One of those substitutes was Wahbi Khazri, who was booed by the away support having stated his desire to leave the club in midweek. The Tunisian has interest from Turkish sides after failing to force his way into the new manager's first team plans.
Grayson said those who wanted out had to prove they were worthy of a move.
"We know where we are with certain players, we know what might happen and what might not happen. If players want to leave the club then they’ve got to put on performances to justify getting out. If you’re not playing well no one is going to take them and that's with all of our players," he said.