Munster coach Tony McGahan and captain Paul O'Connell say the double European Champions must accept full responsibility for Saturday's defeat to Northampton.
Last season's beaten semi-finalists went down 31-27 at Franklin's Gardens in their opener Pool 1 encounter.
Referee Christophe Berdos was criticized by Munster supporters for not issuing a yellow card after Northampton gave away a handful of penalties inside the closing moments but McGahan admits his side have no one to blame but themselves.
"The referee certainly didn't cost us the game. We had everything in our control and we came up short," said McGahan who is currently preparing for a home match against Treviso this Saturday.
"We had four-and-a-half minutes inside the last 25 metres of their try-line and if we were good enough we should have got the points.
"Our kicking out of the red zone was poor. We should have kicked the line more than maybe passing the ball inside the 22 which put us under extreme pressure and, at certain stages, we needed our set piece to be there and we came up a little short.
"So, we need to work on all areas, we wouldn't really be happy with any particular part of our game yet. But we're still moving forward and another week's training will put us in a good frame of mind for Treviso."
Those sentiments were echoed by skipper O'Connell, who was impressed by the manner in which Northampton performed on their return to the Heineken Cup.
The man who led the British & Irish Lions to South Africa in the summer, had no real qualms about Berdos' overall performance and instead focused on the pressure Saints put his side under in attack and defence.
"Christophe is a top quality referee and he was good in the game," explained O'Connell.
"The decision at the end was a bit strange but it was the intensity of Northampton and their ability to take opportunities that cost us, not the ref."
As part of the build-up to next month's Cardiff 2014 Heineken Cup and Amlin Challenge Cup finals weekend, ERC has joined forces with the WRU, Cardiff Blues and adidas to develop an annual grassroots community rugby programme targeting young players.
The Ulster Rugby full back, Jared Payne (No 15), has been suspended for two (2) weeks following an independent Disciplinary Hearing in Dublin arising from the Heineken Cup quarter-final match against Saracens at Ravenhill Stadium on Saturday, 5 April.