Ulster coach Dan McFarland believes his side let slip a golden opportunity to win in France as they slipped to a 29-13 defeat to Clermont Auvergne.
Defeat leaves Ulster needing to beat Bath in the final round of pool fixtures next weekend to be sure of a place in the quarter-finals of the Heineken Champions Cup.
Tries from Alivereti Raka and George Moala helped secure victory for the French side, while John Cooney scored all of Ulster's points with a try, conversion and a penalty.
"We are bitterly disappointed," said McFarland.
"It was a game we had control of in the first half and we didn't make our pressure pay when we should have done.
"If you are going to be good enough to win in Clermont and they are down to 14 men and you kick to the corner and you can't score tries, then you aren't a good enough team to win in Clermont.
"If we took advantage of those opportunities and score, which we are capable of doing, then we'd have had a much better chance of going on to win the game."
"It is really frustrating because they (Clermont) cheat at the scrum, let's face it."
Ulster arrived with real intent and a lovely pop pass from Sean Reidy sent Marty Moore clear, the tighthead prop offloading to Cooney who slipped past two defenders for the opening try.
Clermont scrum-half Morgan Parra was then sent to the sin bin for blatantly infringing at the breakdown with Ulster inches from the opposition tryline.
But the hosts managed to cut Ulster's lead to a mere point with two penalties from Lopez as they reached half-time 10-9 behind.
Clermont took the lead for the first time in the contest when former All Blacks centre Moala charged into the Ulster 22 to put his side on the front foot. The ball was recycled with Raka stretching to touch down in the corner and Parra converting.
Clermont put the result beyond doubt when Moala smashed his way through the Ulster defence to run in from 35 metres out and McFarland was also critical of his side's inefficiency at the set-piece.
"We have to win next week and we have to get a minimum of 20 points," said McFarland.
"There were a couple of occasions in that first half where we didn't execute as well as we needed to to get the points on the board we needed.
"It is really frustrating because they (Clermont) cheat at the scrum, let's face it.
"Sometimes they hit hard, sometimes they hit soft and it's really difficult to deal with, but that doesn't negate the fact that we got pushed backwards."