Sale boss Steve Diamond was disappointed after his side missed out on a LV= Cup semi-final spot due to a late loss at the Ospreys.
The Premiership club needed a bonus point win to reach the tournament's knockout stages and looked like getting it when they led 36-30 with a minute on the clock.
But Ospreys wing Aisea Natoga's try and fly-half Sam Davies's touchline conversion secured the home side a 37-36 victory and ended Sale's play-off ambitions.
Sale held a 28-13 lead at half-time and Diamond, who bemoaned some of referee Craig Evans' decisions, admitted the defeat was a big disappointment but also praised the Ospreys for their fightback.
"I think we probably thought we had the match put to bed at half-time," he said.
"But fair play to the Ospreys they came out second half and ran everything and probably deserved to win in the end.
"It doesn't help that the referee gives us two yellow cards (Ross Harrison and Marc Jones) in the last 10 minutes and they are collapsing mauls all over the show and we don't get any reward for it.
"The last four was there for us. It's very disappointing and we will be licking our wounds on the way back to Manchester.
"But it's the first game we have lost in eight weeks so it's not all doom and gloom.
"I was impressed with the way we got four tries in the first half and then got a fifth, but then we went off the boil defensively."
The Ospreys were happy with the victory but acting backs coach Dan Griffiths believes there is still room for improvement.
"We were delighted with the result but not with some elements of the performance," he revealed.
"That is the standards we want to set for these young men.
"Our attack can put any side to the sword and when we did get in the right areas we were able to come back from 36-20 down.
"We never questioned the effort and the character and we were delighted with the response after half- time."