The west Wales region kicked off their RaboDirect Pro12 season with a 42-19 defeat to reigning champions Leinster.
Easterby’s men appeared on course for an impressive victory at Parc y Scarlets after leading by six-points at the interval.
But Leinster ran riot in the second-half with three tries coming in the space of just 13 minutes.
“We felt we produced some really good rugby in the first half and were in control, but we conceded an early try in that second half, lost our composure and never got control back.
“Our scrum was good, we had good possession and field position and the scoreboard was ticking over.
“We did everything we talked about ahead of the game but after half-time we had a bit of meltdown. We started chasing things, the more we chased things the more we tried to force things and the ball was more often than not lost.
“We can’t fault what we were doing up until half time. But some individual error, composure lost and maybe our leadership was lacking.
“We have to improve our game management, we have to make sure we don’t embarrass ourselves again.
“Mistakes are frustrating and if you make that many it is very difficult to win a game of rugby. When you have a team that capitalise on mistakes like Leinster, you are going to put yourself under pressure.”
The Scarlets woes were compounded by an injury to Joe Snyman. The South African second-row left the field with his arm in a makeshift sling and he will be assessed today.
“We’re not sure on the extent of Joe’s injury yet. We picked up a couple of bumps but hopefully nothing too serious.”