Winger Eli Walker bagged two tries, while Alun Wyn Jones, Dimitri Arhip, Ben John, Dan Evans and Josh Matavesi all crossed for the Ospreys as they claimed bragging rights in the first Welsh derby of the Guinness PRO12 season.
And Tandy was especially pleased with the way his side responded to a tough 9-7 loss away to Ulster last time out.
"I'm really pleased for the boys, in particular," Tandy said.
"After the disappointment of last weekend, when we put in a big effort in Ulster, to come home and back it up with such a performance and get over the line with a five-point win against the high-flying Blues, it's really pleasing.
"Sam played really well. He put us in a lot of good positions.
"We would have liked him to have knocked over a few more conversions, but that's being hyper-critical.
"I thought he made the team tick, albeit off the back of the forwards, who showed a real physical edge.
"Having Sam and Biggs is great for us."
Blues head coach Danny Wilson however, was left perplexed with the way his side dealt with Ospreys' physicality, after watching his side lose their second game running after an unbeaten four-game start to the season.
Wilson pulled no punches after the game and admitted that the Ospreys' power-game had come as a surprise to the capital side.
"Credit to the Ospreys, they were physically more competitive than we were, which surprised me," Wilson explained.
"I didn't think physicality would be an issue, but we were physically dominated in their carries versus ours.
"There were a lot of missed tackles and a yellow card period where we just absolutely disintegrated. There's no way three tries should come out of that period.
"We missed I don't know how many one-on-one tackles during some of those phases, which is not like us, and there were a lot of easy yards for them.
"It certainly doesn't resemble the way we have defended the last five weeks. So I am puzzled."
Guinness PRO12 Final 2017 Ticket Information: Fans can save up to 20% on selected tickets, and prices start at just €30 adults and €5 child, and be booked via www.ticketmaster.ie. For further information visit http://www.pro12rugby.com/final
Guinness PRO12 Ospreys News
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