OK.

koj
③（「―の」の形で）1世紀に一度というほど。「―の大事業」「―の傑作」

it might be worth recording.  i know we normally wouldn't classify 世紀 as adj-no, but i think in this case, it actually would be fair to do so for sense 3?

@@ -26 +26 @@
-<gloss>(most renowned ...) of the century</gloss>
+<gloss>of the century (e.g. fight of the century)</gloss>

In many languages, the equivalent "of the century" doesn't at all mean something like "the most renowned... of the century"
if you don't spell out "the most renowned" bit. so I don't think it's obvious that "世紀の" would have that meaning.

I don't think it's a distinct sense; it's just a way of using sense 1.

google search suggestions for 世紀の

@@ -22,0 +23,4 @@
+</sense>
+<sense>
+<pos>&adj-no;</pos>
+<gloss>(most renowned ...) of the century</gloss>