Both sides went at it in the first half and were locked 5 all at the break.
In the second half Fiji were reduced to 14 players after a red card was shown to half back Rusila Tamoi.
Samoa capitalised on this scoring two tries.
Fiji then had the last say after Seini Tawa crossed over for a try.
The loss means the Fijiana side did not win a single match of the championship.
