I'm not sure how the novels (mainly the Friedman ones?) have described the incident, but its only canonical description comes from "Tapestry", through Q's account. Q tells why the alternate Picard never reached high rank and position in Starfleet, saying he never took risks. He then lists two incidents of risk-taking:
" He never led the away team on Milika III to save the Ambassador, or take charge of the Stargazer's bridge when its Captain was killed. And no one ever offered him a command."
Since Q doesn't list any incidents after the bridge one, we might speculate it was the final step in Picard achieving fame and earning a command. We know little about his rank at the time, though. It simplifies things if we assume he held high rank, because in that case only a few top officers would need to be incapacitated before Picard would be the next in line - but it's also possible that the bridge was isolated and a very junior Picard took command at a crucial moment before the three Commanders and a dozen Lieutenants outranking him could reach the scene.
Interestingly, all canon references to Picard's service as the CO of the
Stargazer are from the 2350s, just before his losing that ship. All references to him serving aboard that ship in an unknown role (basically just the above two bits of heroism) are undated. Perhaps he only held command of that ship for a couple of years, then?
OTOH, "Relics" firmly establishes Picard's first starship command (at the rank of Captain at least) was the
Stargazer. If he only assumed command of her in the 2350s, and lost her soon thereafter, it's a bit odd that he'd next be given the Federation Flagship. Unless his exploits in command of other starships between the
Stargazer and the E-D during the "missing" nine years were really legendary, that is.
But the thing remains that the episodes and movies themselves don't paint a picture of a legendary career for Picard in command of the
Stargazer. To the contrary, three of the four known incidents were failures of sorts: running away from Cardassians ("The Wounded"), losing Jack Crusher ("Encounter at Farpoint", "The Bonding" "Attached"), and losing the ship ("The Battle"). The fourth was a nondescript visit to Chalna ("Allegiance"). I thus doubt we'll ever learn of a succession of legendary XOs to Picard, either... Except in the novels, where a long and legendary career for Picard indeed has been dreamed up.
Timo Saloniemi