"We are a far better team than we showed today. It was a first 40 minutes to forget," said Easterby.
"We just didn't fire any shots in the first-half and we allowed the Blues to win the territory and possession battles. There were far too many errors in our game and they seemed to want it a bit more than us.
"There were a number of individuals who didn't turn up in the first 40 minutes and we ended up compounding one error with another. That allowed the Blues to get their tails up and the penalty count was 11-3 against us in the first-half, which was unusually high for us."
A point blank conversion miss by Wales outside half Rhys Priestland of his own try cost the Scarlets and they also lost Wales full back Liam Williams in a double sending off in the second half with Blues No 8 Robin Copeland.
The one bright spot in the performance for Easterby was the form of Wales hooker Ken Owens, who seemed to cover every blade of grass on the Millennium Stadium pitch.
"Ken was outstanding and he showed how much wearing the Scarlets' jersey meant to him. He had a really good battle up front with Matthew Rees and there wasn't much between the two front rows," added Easterby.
It was a fourth straight Welsh derby defeat this season for the Scarlets, who end their campaign with two more against the Dragons and Blues. The final game against the Blues at Parc y Scarlets could now be a bit of a revenge mission.
"We've got two big derby matches to end our season and we have got to cut out the errors in our game. We could have snatched a win in the end against the Blues, but over the full 80 minutes we simply weren't good enough," admitted Owens.
"We were chasing shadows at times in the first half - it just wasn't good enough. They brought bigger intensity to the game than we did.
"We have tow big derbies to come and we know we are good enough to win them both."?