I Cryptic Crossword Wordplay

[CrikeyMoses]

Help with parsing 8 Down please: Bit by bit, epic broadcast turned implausible, gripping third of viewers (9) P_I_E_E_L
So, Piecemeal (bit by bit): anag of epic but I can't work out the rest. Lame (implausible?) reversed around 'e'? Buy what would 'e' be? A third of 'eye', but not 'eyes'. It's no doubt easier than I'm making it.

[shaneystar2]

third letter of viewers

[Lie-in King]

Piecemeal - anag 'epic' + '(vi)e(wers)' (3rd letter, in) 'lame' (back)

[sandyRoe]

inplausible...lame(as in lame excuse) +e 1/3 of eye + epic. anagram of those

[CrikeyMoses]

Thanks, shaney and Lie-In King. Ruddy obvious but I fell for the misdirection of 'third' as a fraction.
sandyRoe, I did think along those lines but rejected it as the clue says 'viewers'/eyes, not viewer/eye.