Eels coach Brad Arthur said it was unclear how bad Radradra's injury was and ranked the win as one of the most satisfying in his time at the club.
"I have to be honest, I didn't really know what was happening in the second half with who was playing where," Arthur said.
"Daniel Alvaro had to play 40 minutes in the second half as a front-rower and we had all our big fellas out there just filling in somewhere in the line.
"It was a pretty tough effort. Especially coming back from 18-6 down.
"It would have been very easy to say 'we've got enough excuses, we've got blokes all over the place, how are we going to score a try?' But I think that's pretty much how we've played all year."
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Roosters coach Trent Robinson said his side were let down by their failure to hold onto ball and were guilty of inviting the Eels back into the game.
"It wasn't to be for us - I thought we were on top at 18-6 but we went away (from their game plan), and errors and penalties following that," Robinson said.
"And then some big misses on our kick and on the line against Manu Ma'u.
"It's pretty disappointing."
