The victory not only denied England the Grand Slam but handed Wales the RBS 6 Nations title for a second year in a row.
But England backs coach Farrell was quick to point out that Wales deserved their triumph after his side were beaten in every aspect in Cardiff.
"It's obviously the quietest the dressing room has been in a while. Four good wins on the bounce have got us used to a good feeling," he said.
"In the first 40 we had a big part to play in the game. We couldn't sustain any type of pressure in the Welsh half and at 12-3 down we were fighting for our lives.
"But then there was a lack of composure around halfway and they got a break. That made it 17-3, with which normal momentum is hard to get back from.
"And then from 60 minutes we lost our composure, as you'd expect in a game like this.
"All credit to Wales. I thought they beat us in every department.
"We've been pretty good at winning lately. We haven't been in this situation before.
"Seeing pictures after the game, watching the Welsh lift another trophy - good luck to them for that, they deserved it - but we've got to learn the lessons and make sure it doesn't happen again next year."