Mr Ochillo Ayacko will formally become Migori County's third senator since devolution began in 2013, capping an eventful campaign season that lasted 90 days.
That ODM won the election is not surprising even though newbie Eddy Oketch turned what had been dead-rubber poll into a contest.
Yet, like in every by-election, there were plenty of lessons, some which repeated themselves, or serve to warn about future political duels.
Yesterday, Mr Ayacko was celebrating all day, in contrast to last year in August when he fumed after losing the Migori governorship seat to Mr Okoth Obado. Mr Ayacko had lost in the ODM primaries, choosing to contest the seat as an independent candidate. The vote hunt became so violent the electoral commission had to call the two and warn them of possible disqualification.
Dr Ayacko seems to have learnt that no matter the popularity and good pitching, winning an election in some parts of Nyanza on a party other than ODM is more of an exception than a norm.
The scales fell from his eyes when, at the burial of former Senator Ben Okello he made peace with Mr Obado in a deal brokered by ODM leader Raila Odinga. Critics charged the handshake had been for cameras only as the two would renew rivalry. But it also marked a turning point as he retuned to the ODM fold, getting a direct ticket and winning an election for the first time in 10 years.
ODM campaigned for their man and Mr Odinga termed rivals as imposters, marketing his candidate as one who always stood by the party's ideologies.
In the end, Mr Eddy Oketch, his rival, scored 60,555 votes against ODM's 85,234 votes.
It is not every day Mr Odinga chooses to campaign for a candidate in by-elections unless there is a huge contest with another rival party. Take for example the by-election in Kajiado Central where ODM's Memusi Kanchori won in 2015. Mr Odinga went there during and after campaigns to taunt Jubilee who were trying to wrest the seat from the party after the seat's holder Joseph Nkaissery was appointed Interior Cabinet Secretary.
But in Migori? It had been assumed ODM had little job there especially since the party's troubling governor, Obado, who disagreed with Mr Ayacko's nomination, had been in detention.
In the end, Mr Odinga went round the county, holding massive rallies, dancing with the youth and taunting rivals. His man won.
Migori's mini polls were initially seen as a walkover for ODM. Even Mr Odinga went as far as pacifying potential rivals who had lost out in the primaries: He met all of them and they had a gentleman's agreement to support Mr Ayacko.
With rumours swirling that former Rongo MP Dalmas Otieno could run on a rival party, he suddenly got nominated to be a commissioner in the Salaries and Remuneration Commission, a job he accepted, reducing competition for the Senate seat.
But then Mr Oketch reneged on the deal, choosing to contest on a Federal Party of Kenya ticket. His entry was initially overlooked and ODM luminaries even sat on their hands, entering early celebrations. In the meantime, Mr Oketch got Internet traction. His cars, choppers, flamboyance and dismissal of talk linking him to Deputy President William Ruto and Mr Obado were not enough to discourage curiosity.
Ideally, he was a challenger and even his tally suggests he pooled a big surprise. Yet commentators forgot Migori has always been an ODM stronghold. In the 2017 elections, although all the four Luo Nyanza counties refused to take part in the repeat presidential elections, passionate youth in Migori went ahead to weld main highways, barricade roads with heaps of sand and bolted gates to polling centres to ensure voting materials were not delivered. And with a massive number of MPs allied to ODM, and who campaigned heartily for Mr Ayacko, Mr Oketch became a storm.
In the end, ODM lieutenants taunted their opponents as creations of the Internet. Mr Dennis Onyango, Mr Odinga's spokesperson, said: "If every Facebook analyst was right, every candidate would get his/her wish. Netizens just destroyed one of their own in Migori. Yet it is simple: Party members stand with the party. Republicans and Democrats did last week. Democracy has a price."
Uriri MP Mark Nyamita maintained that Mr Ayacko's victory is a testament of the Orange party's popularity in the county and the residents' faith in Mr Odinga.
Critics had excuses such as the detention of Mr Obado - currently facing murder charges - as having denied Mr Oketch the final oomph, or that elections happening on Monday saw a low turnout because most people were at work.
Yet this wasn't the first election where politicians popular online didn't win. In 2016, the Kericho Senate by-election race was seen as a race between Kanu and Jubilee and online warriors posted the Kanu man Paul Sang as a possible winner. In the end, he got half the tally (56,397) of Jubilee's Aaron Cheruiyot at 109,358 votes. Kanu claimed the vote was rigged but didn't challenge it in court.
And in 2013, Mr Peter Kenneth and Ms Martha Karua scored fewer votes than their Twitter followers when they ran for the presidency.
In 2017, after the Independent Electoral and Boundaries Commission (IEBC) announced an electronic and manual vote transmission system, many thought they were backing up against failures. The 2017 election also came on the backdrop of major court decisions among them a directive that a vote announced at the polling station cannot be changed.
Yet the commission's failures to explain transmission of votes, provisional results and final vote tallies meant the presidential election was nullified. In the aftermath, the commission tried to make changes, buoyed by Jubilee politicians who wanted to make it difficult to challenge the election as a process rather than the actual vote count.
In Migori, the IEBC stopped relaying provisional results, meaning polling clerks had to physically move to constituency tallying centres with forms of results to be scanned and sent to the county for verification. Any figures posted either at the county or constituency tallying centres was therefore final.
That however took time. Migori has few roads, many remote villages with rocky terrain and poor Internet connectivity. If this gave a picture of how the 2022 General Election could be, perhaps there should be a change in the law on how long it should take for vote results to be announced.
In Migori still, claims of voter bribery, failure of the Kenya Integrated Election Management System (Kiems) kits - meant to identify voters - as well as poor voter turnout returned to haunt the commission. The good news is observers returned a positive verdict and contestants finally agreed with the results.
On hearing Mr Ayacko had won, one elderly woman at Awendo told Nation journalists she was happy because the man could now build them their bridge and pave their local road. Another claimed there had been no bursary funds for their children and he expected their new senator to provide the money. Yet another claimed the local sugar factor wasn't paying farmers and he expected the new leader to authorise the payments.
In truth, the new senator could, after being sworn in next week, do any of those under his job description. According to the Constitution, senators represent counties, "and serve to protect the interests of the counties and their governments".
They make laws and approve bills concerning counties, determine allocation of national revenue among counties, and perform oversight over national revenue allocated to the county governments.
For a local bridge, it means he could push for more fund to be allocated to Migori even though he may have no hand in actually ensuring the bridge is constructed during his tenure. MPs manage the National Government Constituency Development Fund which routinely has portions for bursaries, but the senator can have no influence over who gets the money unless the local MP agrees.