Southampton will be forced to face Chelsea on Saturday without first choice right-back Kyle Walker-Peters, after the 23-year-old limped out of last week's meeting with Wolves.
The manager confirmed that Walker-Peters will be unavailable for a 'few weeks', with a date for the full-back's return undetermined at this early stage.
Ibrahima Diallo and Theo Walcott remain sidelined, but Hasenhüttl reinforced the confidence he has in his existing squad to perform against Thomas Tuchel's side - a manager he knows well - and the faith he has in his players ability to bounce back from a difficult recent run.
"Still not very happy about what's going on with our injuries," the boss said.
"Kyle Walker-Peters is out for a few weeks, maybe, and that definitely hurts us. He was a big part of our good run and when he was not there we've had a worse run. It's a never-ending story of this season, players getting injured.
"With Ibra [Diallo] and Theo Walcott too, we're missing three important players for our game. We have to trust the players we do have available.
"The first win after such a run is always the most difficult, but the most important, and one we're fighting for."