Now that you posted code, I see your problem. You should have posted your real code and data right in the beginning, remember this for the next time!

The problem lies in a wrong assumption. Somehow you got the idea that you have double-encoded UTF-8, but the octet sequence \320\245\320\260\321\207\320\260\321\202\321\203\321\200 \320\241\321\203\320\263\321\217\320\275 which you have read from a file or the network is actually simple encoded UTF-8. Trying to decode it twice in a row is a programmer mistake.

decode 'UTF-8', "\320\245\320\260\321\207\320\260\321\202\321\203\321\200 \320\241\321\203\320\263\321\217\320\275" returns the Perl character string Хачатур Сугян. Operate on that result.

Completely read http://p3rl.org/UNI to learn about the topic of encoding in Perl. Forget that the pragma utf8 also has some functions; you must use the Encode module only.