The Aviva Premiership’s bottom side were thrashed 35-7 at Franklin’s Gardens, with Saints running in five tries.
James Craig, Alex Waller, Jamie Elliott and Lee Dickson all dotted down, with Jim Mallinder’s men also registering a penalty try.
Irish eventually got on the board when hooker David Paice scored late on, but it was scant consolation for the strugglers.
And Coventry said: “I thought we were pretty poor.
“A little bit of ill-discipline from Halani (Aulika, who was sin binned during the first half) cost us and they took those two tries pretty well.
“It sums up where we are at the moment; we are not taking our opportunities to score when we are in vital parts of the field and maintaining pressure on the opposition is not something we have been able to do regularly.
“There is a lack of confidence in our game at the moment, and in front of a big crowd against a Saints side with a chip on their shoulders after losing at our place, we needed to be perfect.”