Booth’s side scored twice to win on the road at Cardiff City Stadium with star man Ifan Phillips crossing for a first-half try before a penalty score.
Fly-half Stephen Myler added a conversion and a penalty.
Booth said: “It was good reward for the effort we put in during the game and I am delighted with that.
“You build a lot of your performances on set-piece and we were dominant in that area which is fantastic.
“It makes the game a lot easier to play on the front foot than the back foot and you make yourselves harder to beat.
“The exciting thing for me is this group were disappointed afterwards they were not further ahead on the scoreboard.”
Ospreys captain and Wales flanker Justin Tipuric said: “We know we’ve been dominant set-piece wise in the Challenge Cup so far, but to do it in the league against such a good side as Cardiff Blues was outstanding.”
Man of the match Phillips said: “It’s brilliant to get the win down here. Cardiff Blues are a great outfit.
“The set-piece was important. We’re all pushing each other and it’s great to have competition for the number two jersey.”
Cardiff Blues had forwards Seb Davies, Dmitri Arhip and Scott Andrews yellow carded in the second half as they played most of the period with 14 men.
All they could manage was a penalty from fly-half Jason Tovey.
Blues head coach John Mulvihill said: “In these games we need to play well enough to deserve to win and we did not play well enough.
“We can’t give away 19 penalties and three yellow cards and come out on the right side. I was really disappointed with our discipline.
“We need to clean that up. The intensity was not here for for a lot of periods and the Ospreys did have that.
“The venue was fantastic. It did not get the spectacle of rugby, but it’s an awesome venue to play in.”
