Jaissle’s side were unbeaten heading into the game at Elland Road despite having had a turbulent summer transfer window.
They were very much second best against Leeds, however, with an own goal from Lewis Miley, along with strikes from Jayden Bogle, Dominic Calvert-Lewin, and Noah Okafor securing a comfortable win for the West Yorkshire club.
Speaking to Sky Sports after the game, Jaissle admitted that the defeat was ‘difficult to digest’ and urged his young squad to learn from it.
"That's football, that's the Premier League. It was clear from the start and I said many times we would have ups and downs and challenges along the way. Tonight we faced a challenge,” he said.
"It's tough, really tough, difficult to digest. This is a chance to learn straight out of it and there's not much time to the next match, which is good.
"With our young squad there will be ups and downs. Leeds are so intense, especially at home and we could not match that physicality in the first half.
“I don't want to have excuses; we need to learn and be better. We missed the fundamentals."