A proposal not to align with the Congress, backed by Mr Yechury's predecessor Prakash Karat, won in a vote. Mr Yechury had backed a rival draft that proposed an alliance with the Congress and other Left parties to take on the BJP in the 2019 national election.
A Cold War within the CPM is not a new hostility. To Congress or not to Congress has long divided the party which turned into a Kerala versus Bengal fight. But the divide has deepened.
The Bengal lobby - once powerful, unshakeable in the bastion -- is now underdog. Kerala and others like Andhra, Telengana and even Tripura which played second fiddle over the years can now tell Bengal a thing or two.
They had tried to, in the past, in a comradely fashion. On Nandigram and Singur, for instance. But the Bengal lobby -- then invincible -- had swatted them away.
It is now payback time. And how!
There is a break in its own ranks. At least two Bengal CC members voted against the Yechuri draft.
A Kerala leader had fainted and fallen down last week in Ernakulum and was admitted to hospital. He almost skipped the CC but was urged to come for the CC. In Kolkata, he called in sick on Friday and Saturday. But, on Sunday, he was persuaded to come vote.
In the middle of Saturday afternoon, day two of the CC meet, Prakash Karat left to call on former West Bengal chief minister Buddhadeb Bhattacharjee who is very unwell. What transpired inside is not known, but the buzz is on.
Buzz, that Mr Karat did not go only to ask Mr Bhattacharjee about his health. Buzz, that he urged Mr Bhattacharjee to step in to stop the fight, tell the Bengal lobby, calm down, go with the flow, avoid voting. There is time before 2019.
Buzz also that Mr Bhattacharjee declined to intervene but urged Mr Karat to thrash out a formula to avoid voting. But he clearly drew a blank.
Mr Karat went back to the CC meeting and the debate was so bitter, a Politburo meeting was called in the evening.
That's where Sitaram Yechury threw in the towel. Position untenable, he is believed to have said, if his point of view is repeatedly rejected. In October, 32 CC members had spoken in favour of Mr Karat's draft resolution. 31 had spoken for Mr Yechury's.
In the last six months, not only had his draft been rejected in October, the Politburo failed to find a consensus in December too. In between, Mr Yechury gave up a third term in Parliament -- the CPM's rules say no more than two terms. And the rulebook prevailed just like it had when Jyoti Basu was offered the Prime Minister's post in 1996.
Buzz in the Bengal lobby is that Mr Yechury was not allowed to resign. Not because they wanted him as general secretary still but because his leaving now would have turned him into a martyr in the eyes of many ahead of the April party congress.
At the party congress, if he quits, that's fine. The names of two members of the Politburo are already making the rounds as likely successors.
They were the two who ensured peaceful voting at the CC - BK Raghavulu and Brinda Karat. Everything was comradely. Just a tad slow. The vote and count should have ended by noon. It all went on till 1 pm. Which is why most CC members had to rush off to the airport without lunch.
At 3 pm on Sunday, Mr Yechury held a press meet confirming that his rival camp had won, the first time in over 40 years that a general secretary's draft resolution was defeated. He refused comment on reports of his resignation offer. But he got the vote count wrong.
He said he had lost 55 to 33. It was actually 55 to 31.
But back to what if he quits in April? All eyes are on Mr Raghavulu and Ms Karat. Both are Politburo members, both high profile, both hugely experienced. And if Ms Karat is chosen, she will be the first ever woman CPM general secretary.
But nothing is certain. Analysts point out that the composition of the delegates at the Congress will be different from that at the CC. And Mr Yechury and his supporters in the party may still push through amendments to change the Congress stand.
Some say, Mr Yechury's version of the draft political resolution may even end up being being placed at the party congress.
The middle pathers are still holding out hope that, while an electoral deal with Congress is very difficult to push through, a conditional understanding may be acceptable to most. And may become more acceptable as 2019 nears.
But there has been an ugly fall out to Sunday's CPM vote.
At least one newspaper has put it in black and white. The Telegraph headline says, Yechury loses, Karat wins, so does Modi. And a comment doing the rounds in whatsapp groups is, # CPM loses after valiant fight. In a stiff contest, BJP captured CPM central committee with 55 votes to 31
Of course, it is only chatter.
But for the CPM, battered and beaten in the last decade, this is chatter it can perhaps ill afford ahead of the 2019 elections if it wants to play a meaningful role in the opposition's avowed bit to oust the BJP.
Of the two states it rules, Tripura has Assembly polls one month from now. The BJP is snapping at the CPM's heels. But the CPM will not have any truck with the Congress. A three-way vote, four-way if you count the Trinamool, and who knows, someone like Mamata Banerjee may suddenly blindside Manik Sarkar, Tripura's four-term chief minister.
The CC members should have popped into a movie hall near the party office and watched this film on Winston Churchill that's running this week. Darkest Hour.
The film ends with a Churchill quote the CPM may have found edifying.
"Success is not final. Failure is not fatal. It is the courage to continue that counts."
Courage to continue the fight
Of course Churchill was talking about the Nazis. Here, its a war within.
(Monideepa Banerjie is NDTV's Executive Editor - East based in Kolkata.)
Disclaimer: The opinions expressed within this article are the personal opinions of the author. The facts and opinions appearing in the article do not reflect the views of NDTV and NDTV does not assume any responsibility or liability for the same.