Head coach Steve Tandy says Ospreys need "an attitude shift" ahead of next Saturday's game against Pro12 play-off rivals Ulster.
Ospreys' 35-17 loss to Cardiff Blues was the first time they had been beaten by their Welsh rivals since 2010.
"There will definitely be a reaction in around that, in particular our training," Tandy said.
"I think there will be a lot of individual reviews where we need to be."
Tandy added:" But ultimately we've got to have an attitude shift if we're going to have any chance against Ulster."
But Tandy's side remain fourth in the Pro12 and are one place above Ulster, the team they host at the Liberty Stadium on Saturday, 29 April.
"Miraculously, after losing three games on the bounce, we are still in the top four," Tandy added.
"We've got three or four days now where we've got to take a long hard look at ourselves.
"I definitely think there will be a huge reaction against Ulster but it's going to be a quality Ulster team who will be desperate to knock us over.
"It's going to be a tight game and every game seems like a knockout game and we don't seem to be getting that right at this minute in time."
Tandy was without 15 injured players for Saturday's game at the Principality, including fly-half Dan Biggar who was missed the game after suffering a head injury against Leinster.
With so many absentees, Tandy admits he is unable to make major changes to the side for the game against Ulster.
"We haven't got a lot of opportunities to change people and that does hinder us a little bit." Tandy said.
"With some of the boys there may be an element of a little bit of fatigue in and around some of the young boys."