Tom Coventry described the London Irish dressing room as "like a morgue" after their relegation from the Aviva Premiership was all but confirmed following a 32-25 defeat to Harlequins at the Madejski Stadium.
Irish had won just four of 20 matches before playing Quins although they threatened a memorable comeback after rallying from 19-3 down to lead 25-22 in the second half.
However, Nick Evans levelled matters with a penalty and then added the extras to fellow substitute Kyle Sinckler's 70th-minute try.
London Irish all but relegated from Premiership after Harlequins defeat
01/05/2016 AT 19:23
The loss leaves the Exiles rooted to the bottom of the table and only the unlikely event of Bedford winning this season's Greene King IPA Championship would keep them afloat.
Other Championship title hopefuls Bristol, Yorkshire Carnegie and Doncaster have all met minimum standards criteria to play in the Premiership next season but, with Bedford not applying to have their ground audited, there is a lifeline lingering for Irish.
But coach Coventry said: "It's a sad day for the club, the dressing room is like a morgue and it's hard to describe the feeling and it's a tough place to be.
"The boys gave everything but we weren't able to keep Quins at bay as they were able to break our defence too easily at times.
"Before rounds five to six, we were getting trounced, since then we've steadily improved but we haven't been good enough to finish sides off."
Coventry knows his future will be a hot topic of discussion in the coming days.
"There will be a big process of review, I'm responsible for the results and the buck stops with me," he said.
"We've made some progress and I'd like to remain at the squad and keep the present squad together."
The bonus point victory for the Quins ensured that, if they beat Exeter at home next weekend, they will have a European Champions Cup berth for next season without having to rely on beating Montpellier in the final of the Challenge Cup.
Director of rugby Conor O'Shea was delighted to secure a crucial win but had considerable sympathy for his former club, whom he had served as a player and coach for many years.
"We wanted to nail our European spot for next season so our job was to send Irish down today," he said. "We knew it would be tough and it was as we got on the wrong side of the referee.
"I came to London 21 years ago and Irish were promoted to the Premiership that season and they have been there ever since.
"I hope they can come back as soon as possible for they have a quality squad, but it just shows how brutal the Premiership competition is."
On the clash with Exeter at the Stoop next Saturday, O'Shea added: "It's now in our control and destiny and it's going to be tough but the players are always fresher when they have something to play for.
"It's far better than being involved in a dead rubber."
Reflecting on the prospect of the club playing Championship rugby next season, Irish chief executive Bob Casey said: "This is a sad day in the history of this great club.
"Relegation was not part of our plans, but we have to be honest, as hard as the players and management have worked, we haven't been good enough this season.
"The foundations at London Irish are in place.
"We have excellent facilities, a thriving academy programme and outstanding support staff. Unfortunately, the progress of our rugby programme has suffered a setback this season in what has been the strongest Premiership in a long time.
"We will do our utmost to ensure we return to the top tier of English rugby at the first time of asking."
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