Joe Schmidt says Ireland must "get better fast" if they are to hold any realistic World Cup hopes.
The head coach saw his side ship a record-breaking 57-15 defeat to England, the second dispiriting loss in a row to the Red Rose after the Six Nations reverse, after which Schmidt said they were "bullied".
This was yet another playground-style mismatch as Eddie Jones's men ran in eight tries, with Ireland losing scrum-half Conor Murray and prop Cian Healy to injury.
Speaking to RTÉ Sport's Michael Corcoran, Schmidt said: "We fell off 34 tackles, we couldn't really get our set-piece going, I thought we were a bit unlucky in the first couple of scrums.
"In the first 20 minutes I thought we were in the game, it might have been a one-score game.
"It was even leading up to half-time, at 15-10, and then Conor got hurt and we were down to 14 when they scored, they worked the overlap well and we’ve got to be able to sometimes defend with 14 well enough to keep them out.
"So 22-10 at half-time, I felt if we could just even win the second half it would be something but we fell off way too many tackles.
"We gave them access into the game far too often, coughing up ball or not nailing our set-piece.
"When you are not doing that it is very difficult.
"We knew [they were ahead in match-fitness], a number of their players have played a couple of games.
"So we anticipate that we can get better and we are going to have to get better fast because that is nowhere near good enough."
While Ireland started a largely second-string team in the win over Italy, which came at the cost of injury to Joey Carbery, and England had two Tests against Wales to their name, the manner of the defeat could not be blamed squarely on just that.
"We were really flat, there was no real energy in our performance," said the head coach, who put his squad through the paces in an eight-day training camp in Portugal.
"You don't have to be very far off to be pretty quickly chasing your tail, particularly against a good side like England
"I know we were a little bit heavy-legged, it was part of the challenge for the players to get up for the game and still be really competitive.
"We will start to taper now and try to get into a really peak-performance state and try to build through these next two games against Wales so we can be ready to go against Scotland in four weeks’ time."
On the injuries to Murray and Healy, he said: "We' didn’t mean to put [Conor] back on, he passed his HIA, he’s okay but we’d planned to give Luke another good outing anyway.
"Cian, his x-ray is normal but obviously there’s a bit more to look at with him spraining that ankle but what was more promising than Joey was that he was at least able to walk from the pitch.
"He’s sore now but if we can keep the swelling down and get a decent look at it hopefully he’ll be back in a shorter time-frame than Joey."
Ireland now face a home and away double-header against Wales, starting with a visit to Cardiff on Saturday.
He added: "We came here before the last World Cup and we didn't play well and we copped, not the size of the hammering we did today, but the score probably flattered us [21-13].
"A lot can change in a couple of weeks – we saw that with Australia and New Zealand – so we are hopeful that we can gather some momentum reasonably quickly and to be honest we are going to have to."
