The 26-14 win highlighted the return of former All Black Zac Guildford to somewhere near his peak, with his work rate and running off the ball superb, while Luke Masirewa was unstoppable at times.
The tournament is the dress rehearsal for the men's and women's provinces before next weekend's Bayleys National Sevens at Rotorua International Stadium.
Bay of Plenty fielded two men's teams and a women's team on Saturday. The top men's blue team lost the plate semifinal to Auckland 33-21, the men's gold team went down to Wellington 28-26 in the bowl semifinal, while the women lost the cup semi 32-7 to champions Manawatu.
The Samoans are in Mount Maunganui on a five-day training camp.
Tietjens was delighted with their progress since they flew in from the islands.
"The intensity or the level of sevens they play over there means they have got to make shifts in two areas around fitness and also around nutrition. They work hand in hand," he said.
"So getting them here is to put them in this tournament and play them at a different intensity, against different types of potential New Zealand players they are going to strike in the World Series.
"Some of these boys have never been off the island. They are a pleasure to work with. They will spend five days here at the High Performance Centre and I am using this as a selection tool to go to Wellington.
"We have another week here before then from the 17th."
Tietjens' son Paul coached Bay of Plenty Blue to within a minute of making the Cup semifinal before Northland snatched it away with a try at the hooter.
"It was potentially just key moments against Northland and against Counties. Looking after the ball, being a little bit more patient which cost us in the end, which are key learnings heading into the nationals," he said.
"This tournament here is really, really good to see where your players are at as regards to your combinations that you have within your side. Today was about trying out a few combinations and seeing how players adapt to playing at this level.
"You definitely see some real positives at this tournament to build and progress your side, start building a good team culture towards next week. You want to go in confident but no one has ever won the nationals after winning this tournament."
Bay of Plenty women's coach Victoria Grant was equally upbeat ahead of the nationals.
"I was really pleased with the girls today. We had different girls from our regional sides who have been training hard and had a shot at being one of the 12 for nationals next weekend," she said.
"We lost the semi to Manawatu but it was good because we played Auckland (lost 12-20) and Wellington (won 17-7). They are both in our draw for nationals so it was good to play them and also for the girls to play Manawatu. They have been national champions for a few years now so it was good for the girls to be exposed to that level."