Sense motive vs invisible blade for raging and frenzying, does it work?

[wraith8]

I have a frenzied berzerker/Bear Warrior.
I face an invisible blade who feints then attacks.

My friend argues, "Since i'm frenzying and raging, I cannot use sense motive (int) to detect his feint"

I argue: "Sure it isn't mentioned in the rage descripion like intimidate is, but since i'm adding my bab to my sense motive check, i'd assume raging doesn't prevent me from sensing his feint"

What do you think

 

[Sejs]

Sense motive is based on Wis, not Int.

Detecting someone's feint in combat doesn't require concentration.

Your friend is mistaken.