Kiss 'angered' after loss to Saracens
Their 17-33 defeat at Allianz Park has left Ulster needed a big win against Oyonnax in their final fixture to keep alive their hopes of reaching the knock-out stages.
Kiss couldn't hide his disappointment after his side conceded four tries against Saracens and admits the pressure is on his side to produce next week.
"We had a chance to place ourselves in a better position in the pool this weekend but we weren't up for it," said Kiss.
"We have to live with that. It hurts because Saracens have done it to us twice but we have to make that hurt matter and use it next week.
"I'm disappointed because I would have expected more."
Saracens flyhalf Owen Farrell produced another fine display as they ran-in four tries against a disjointed Ulster defence.
Kiss added: "When we got to the part of the game we would have liked to have got to more often we certainly exposed the spaces we were after.
"We just weren't clinical enough. There was a period of play when we got a few penalties and got into their corner but we didn't use our set piece to give ourselves a platform to play from and stay up there.
"That's what Saracens do well. When they get into good positions they stay there but we gave away that position too often.
"It allowed them to get the try in the corner which give them a lead at half-time.
"Fair play to Saracens they put you under pressure and that's why they are the best team in Europe.
"We fell by the wayside far too easily in the second half, we reacted to their pressure rather than keeping our composure.
"We tried to fight our way out of it rather than staying composed."
Source: @ChampionsCup
