Best and co did take their foot of their gas in the closing 20 minutes however and the Scarlets restored some pride with tries from Gareth Davies - who scored a fine solo effort - and Sione Timani.
Nonetheless, Ulster are into the final at the RDS where they will face either Leinster or Glasgow Warriors and hooker Best - who was named man of the match against the Scarlets - is determined to finish the job.
"We put ourselves in a position to get a home semi-final, we knew that the support would be massive for us and ultimately this was where we wanted to be," he said.
"We wanted to win silverware this year and this is our last crack at it.
"In two weeks' time we got to the RDS and we want to win, we felt this team was good enough to win something at the start of the season and while obviously we wanted to win everything, this is our thing now so we're delighted to be in the final.
"We had to try and exert some dominance up front because they have a very exciting back line and I thought we did that for large parts.
"When we look at it we'll be disappointed about the last 20 minutes or half an hour but ultimately we played 50/60 minutes of great rugby and we're into the final."
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