Centre Jonathan Davies grabbed a try on his 100th Scarlets appearance, while flying wing George North crossed twice in their 28-20 triumph.
But despite claiming victory and the resulting four points were the most important thing, Easterby still had qualms with his side's display.
"It was a frustrating afternoon at times. We were comfortable for the first 35 minutes and did exactly what we wanted to do," Easterby told Wales Online.
"We got a lead and played in the right areas but then we conceded a soft try which brought them back into the game and they levelled things on half-time.
"We were frustrated at half-time because we felt we were dominant in all areas but we did not gain our reward ourselves overall.
"In that final minute we were looking to get off-loads that weren't there and we were a bit loose.
"At half-time we wanted to be a bit more conscious of going through the phases more. We showed that little bit of class to get away from them but we couldn't quite get that bonus point.
"But it was definitely four points won rather than one point dropped."
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