Meaning of "all game and bottom" in Byron's "Don Juan"

Question

From Byron's Don Juan:

That drinks and still is dry. At last they perish'd --
His second son was levell'd by a shot;
His third was sabred; and the fourth, most cherish'd
Of all the five, on bayonets met his lot;
The fifth, who, by a Christian mother nourish'd,
Had been neglected, ill-used, and what not,
Because deform'd, yet died all game and bottom,
To save a sire who blush'd that he begot him.

What is the meaning of "all game and bottom", especially of "bottom"? "All game" means "quite willing to meet his death", I think. What does "bottom" mean (or "all bottom")?

I looked in the dictionaries, but haven't found any suitable meaning. My only guess is quite weak - that he fell "bottom-most" and all the others fell upon him, or maybe that those who killed him fell upon him. But that is apparently not the case.

Answer 1

My OED (1st edition) gives under sense 14 for "bottom" the following:

Physical resources, 'staying power', power of endurance; said esp. of pugilists, wrestlers, race-horses, etc.

It gives five citations of this sense, dating from 1774 through 1852, including one to this passage in DJ. Others: "Though the Savages held out and, as the phrase is, had better bottoms, yet for a spurt the Englishmen were more nimble and speedy." "They ... have their manes and tails cropped ... under the supposition that it adds to their strength and bottom" and "For solidity, bottom, and a courage that never wavers, they [British troops] are incomparable".