British Rules of Engagement: Frigate vs. Frigate

While researching the USS President's capture, I found some discrepancy in what happened.  Had the President just engaged the Endymion or the whole British fleet?  You'd think one of our "Super Frigates" could take a regular British frigate (unless it was one of their "Super frigates" they started launching later in the war).

Obviously, one American frigate fighting a whole British squadron would not be expected to win.

But, did it fight the whole squadron?

I came across mention of British regulations requiring that equal numbers of ships being involved in battles.  The HMS Endymion was the first to engage the President.  Both ships came out of the fight seriously damaged, but Decatur knew he would then have to engage the rest of the British fleet in succession, a fight he knew he couldn't win which led to the surrender.

I'd never heard of the one vs. one ship engagement rule,. so will keep my eyes open for further mention mention of it.  But, it would seem to me you'd always want to press home an advantage like numbers superiority in battle.

And, the President was one of our capital ships and Decatur a big naval hero.

Oh, Well.  --Brock-Perry