If there was a path to upset victory in yesterday’s Boston mayoral race, it was never going to run through Michael Flaherty’s “Good/Better” campaign, which always seemed to suggest that he’d simply be a better version of what voters had come to like about Tom Menino. If a 16-year incumbent is vulnerable, it is because voters are hungry for real change, and Flaherty was not credible from the outset as an authentic agent of change.

It was a poorly kept secret that the Menino campaign was more worried about the prospect of facing Sam Yoon in the final election. In internal Menino campaign polls, the wonky second-term city councilor scored high with voters when they were asked which candidate was most likely to bring real change. Yoon, who finished out of the money in the preliminary election but went on to endorse Flaherty and play deputy-mayor-in-waiting on the unofficial “Floon” ticket, had the right profile to tap voter hunger for change and innovation in city government. We’ll never know whether Yoon, who often seemed better as a concept than candidate, would actually have caught fire.

But it was never really in the cards for Flaherty to pick up the sort of momentum that would have been needed to topple a hugely popular incumbent. Flaherty and Menino registered much lower than Yoon as agents of big change in the mayor’s campaign poll. Remarkably, however, the 66-year-old four-term incumbent was seen as slightly more likely to bring change than 40-year-old South Boston city councilor charging at his heels.

Armed with that sort of insight, once Flaherty — lugging all that baggage from his alliance with the reform-reviling firefighters’ union — edged out Yoon for the right to face Menino in yesterday’s election, the Urban Mechanic mayor knew that, barring any major gaffes or controversies, he could put away his tools and practically set his campaign bus on cruise control.