Cardiff City boss Russell Slade said he was 'sickened' by his side's first-half performance in the 3-0 defeat at Bolton on Tuesday.
Liam Feeney put the Trotters 2-0 up inside 36 minutes, with Matt Mills adding a third late on for, one from bottom, Wanderers.
Cardiff, still 11th in the table, have won all three home matches under Slade, but have yet to win away this season.
"It's disappointing, sickening really, the first 45 minutes," said Slade.
"But the second 45, for half an hour, we were certainly on top and we never gave up.
"That was the positive but we have to be better than that. We have to learn from that immediately."
|Cardiff City manager Russell Slade:|
|"We had a little bit of a soft underbelly if I'm honest."|
Slade's only other defeat, in the five matches since he took over, came away against Millwall.
At the Cardiff City Stadium he has overseen victories over Nottingham Forest, Ipswich and Leeds.
The former Leyton Orient boss says his side must be "mentally tougher" if they are to achieve better results on the road.
"Our attitude has to be stronger than that," said Slade.
"We know our approach has to be with a focus and greater hunger than what we showed to start the game [against Bolton].
"We had a little bit of a soft underbelly if I'm honest.
"If they [Bolton] pressed us, then sometimes they nicked the ball off us today and we've got to be mentally tougher than that, to deal with that.
"I mean they are the home team, they are going to do that."
Cardiff's next match is away to Birmingham City on Saturday 8 November.
While the Bluebirds were losing against Neil Lennon's side on Tuesday, the Blues knocked Watford off the top of the Championship with a 2-1 win.
The result moved Gary Rowett's side to 22nd in the table.
Slade says he is considering making changes for the trip to St Andrews.
"You can't really have that first 45 minutes in any season," said Slade.
"We have to get over that quickly and if that means changes then that will be the case."