Ospreys also broke their try record by running in 11 scores, with Sam Davies grabbing his first two tries in senior rugby.
Jonathan Spratt also bagged a double as the Ospreys turned up the heat in the second half to leave Rees a happy man.
"First quarter we were disappointed that we forced a couple of things and then manufactured three decent tries," he said.
"We did ask second half for us to put them away and be a little bit more ruthless than what we were and we did that.
"It is an extreme example but last year we did decry the fact that we couldn't get winning bonus points and we've nailed that pretty early on.
"We have done four games with winning bonus points now with eight games to go and we are accumulating points there and it is crucial."
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