i obtained the highest ever teaching score rating for a tutorial that i had taught, beating other professors. Is there any chance my supervisor will see me as a threat?

Congratulations on achieving that score! I wouldn't worry about this. Have you always had a good working relationship with your supervisor?

i do. but the manner in which i was asked as to why my teaching score is high kinda triggered me. The tone was an interrogative one, caught me off-guard.

Your supervisor is most likely concerned that you are spending too much time teaching and not enough on your PhD. I highly doubt your supervisor us threatened by you.

Perhaps your supervisor is annoyed that you outscored them by a huge margin.
Did you tell him your score?
Might be a touch of jealousy.
You should downplay winning stuff like this when you know for a fact that you have outscored those who are supervising you.
These sorts of awards are usually pretty useless in the scheme of things but academics take them far more seriously than they should because there is rarely an opportunity to get feedback on their work. Hence you get awards for "best poster", "best presentation" etc which cause nothing but embarassment, resentment and an opportunity for research group politics.

Honestly, I wouldnt bet on that.
Pehaps not "threatened" but more than likely a bit pissed off.
A lot of pettiness exists in academia.
TBH they should just dispense with this sort of ridiculous award in the first place.
There should be no awards in science because there is no good way to compare two pieces of work.
Just like music. Can you imagine trying to decide whether Bach, Beethoven and Mozart were to be awarded a Grammy?
Best tutorial? Come on. Seriously? This sort of thing is all just nonsense.

I disagree with you for once pm33! If the students provided the ratings for the best tutorial, then they obviously really did consider Iwan's to be the best - which is great! (Especially if they are the same group of students - but regardless actually).

I'd be very proud to have that on my CV.

As for the sup. I think academia makes people a bit insecure and so things like jealously, pettiness and power tripping are rife. I'd say just take pride in your amazing achievement and (mentally) stuff your supervisor!