Carlos Carvalhal said his side have had a tough week after their 2-0 defeat to Leeds at Hillsborough.
The away side took the lead in the second half through Marcus Antonsson before Chris Wood sealed the victory with five minutes to go.
Before and after the first goal, though, the Owls had chances to register.
Carvalhal said: “Today we created enough chances to win the game.
“The team that took the lead can always try and keep hold of that and it was Leeds who scored first.
“We kept creating chances as we tried to get the equaliser, but it meant that Leeds could counter-attack the spaces at the back and this is when they scored the second goal.
“I am not one for excuses as you know but we have had a tough week.
“We wanted to give the same as we did against Aston Villa and Norwich, but the balance of the team is not at 100% in this moment.
“At the moment we have players who are just arriving and the team are at different stages in the process.
“Some players haven’t had much time in pre-season, so they are catching up with the conditions, but this is normal for this point in the season.”