This ended up not being enough, first, because Republican Troy Balderson ran up huge numbers in his home county of Muskingham (another blue collar, small town county), and also because Balderson mostly matched Trump's vote share in all the other blue collar counties.
O'Connor appears to have improved in these areas by capturing much of the vote in them that had gone to a third party candidate in 2016, but nonetheless, he did outperform Clinton in three of these counties, which helped him to close the gap compared to 2016, even though Balderson did come close to Trump's share of the vote in all these counties.
I asked pollster, Jason McGrath, whose firm GB Strategies did O'Connor's polling, how he did this.
McGrath told me that one important ingredient was a focus on jobs, healthcare, and infrastructure spending.
McGrath noted that one reason for the improvement was that Republican turnout in these areas was lackluster, while the (much smaller) number of Democratic voters in them were more galvanised.
But he also said O'Connor had been able to win over some independent voters who supported Trump and moderate Republicans with a focus on issues.
"We had to run on real issues and be grownups and talk about things that matter to people," McGrath said.
To be sure, these O'Connor gains in tough areas didn't really upend the larger pattern we've been seeing in the Trump era.
As Ron Brownstein demonstrates, this race showed that Trump continues to deepen the polarisation between suburban/urban areas on the one hand, and exurban/rural areas on the other.
Once again, the Republican ran up huge, Trumpy totals in blue collar white strongholds, especially relative to Mitt Romney's totals among them in 2012, while losing ground relative to Romney in more educated, suburban, white collar areas.
But still, O'Connor did improve on Clinton's performance in some of these areas, even if it may not have been enough to win.
O'Connor's approach carried echoes of another Democrat who pulled off a huge upset in Trump country - Conor Lamb in western Pennsylvania.
Lamb emphasised jobs, unions, and social insurance to prevail in hostile territory.
O'Connor ran ads that vowed to rebuild infrastructure, made a personal case for improving access to healthcare, and argued that congressional Republicans are doing nothing for "working families".
The route to a Democratic House majority probably will have to run through many more educated and suburban districts.
But for Democrats, the map is also getting broader because they are putting some districts with a lot of working class white voters in play.
Democrats have been consumed in an argument over how to reach out to working class whites without backing off their commitment to minority rights and immigrants.
In this district, Republicans worked hard to tar the Democrat as the party of crime and open borders.
In the face of these attacks, O'Connor stressed a bread-and-butter Democratic message about jobs, infrastructure, and healthcare.
The fact that he came so close in Trump country will mean that other Democratic candidates will be looking at his approach to winning back these voters, even if doesn't look like it was quite enough.
