Aditya Thackeray (left) is confident of Shiv Sena's victory
At a makeshift Shiv Sena campaign office in the north Mumbai suburb of Borivali, Aditya Thackeray pulls over in a black BMW. The Sena youth president is surrounded by dozens of supporters on bikes, holding up saffron flags and banners.
Borivali is alien turf for the Sena. With a high number of Gujaratis and Marwaris, the constituency has been a BJP stronghold for the last three decades.
In 2009, despite the party's poor showing in Mumbai, the BJP's Gopal Shetty won by 30,000 votes. Shetty is now a member of parliament and Vinod Tawde, one of the BJP's chief ministerial aspirants has been given the Borivali ticket.
Which explains Aditya's Thackeray's presence - Borivali has become, like so many seats across Maharashtra, a grudge battle. Tavde is one of the leaders the Sena blames for the breakdown of the alliance.
Aditya claims that these "two-three leaders" (who he refuses to name) are "not trusted by anyone even within the BJP" and that the Sena will ensure their defeat.
Tawde on the other hand told us that the responsibility of the break up began the the day when Shiv Sainiks pressed for Uddhav Thackeray to become the Chief Minister. That day the flexibility of Shiv Sena (over seat sharing) was lost.
And yet to take on the BJP in Borivali, the Sena had to fall back on a BJP import: Uttam Aggarwal, a high profile chartered accountant.
Aggarwal responded with anger when asked by NDTV why he crossed over to the Sena. "How many bloody people were there in the line (as BJP candidate for the Borvali seat) with even 5% caliber of my networking. I didn't ditch the BJP, they don't know how to respect their educated people and they want to serve the whole state and country?"
Vinod Tawde, however, seemed nonplussed. "I don't think Uttam is a strong candidate because he was basically BJP worker, he has worked with us and if he is a CA I am an electronic engineer."
If the Sena-BJP rivalry is sharpest in Mumbai, its because the city has been a Congress-NCP bastion, now seen as up for grabs. In the 2009 assembly elections, the BJP-Sena won only nine of Mumbai's 36 seats. As allies, the BJP had contested 13 seats and the Sena the balance 23. Today, they are no longer bound by seat-sharing formulas. But finding candidates and setting up ground networks in each others' turf is not proving easy.
The Sena claims that despite Borivali being alien territory, they have a well-entrenched network in every locality of Mumbai. Aggarwal asked one of his team members to take out his mobile phone to show us numbers of Sena grassroot workers in the Borivali area.
Tawde too claimed that the BJP has a "fantastic network of workers" of the BJP, but also the RSS" which he said is "working for maximum voting in the elections".
Across the political fence, the Congress and NCP are also grappling with the same dilemmas: bitterness, grudge contests and imported candidates. Added to this is a strong backlash against having done little for Mumbai despite 10 years in power.
A typical example is Kripashankar Singh, the former minister and former president of the Mumbai Congress fighting from the Kalina seat, which he won last time.
The NCP leader and minister Nawab Mallik claims he coveted the Kalina seat in 2009 but was asked by the NCP leaders to give it up for Kripashankar.
Now the gloves are off - Nawab Malik's brother Abdul Rashid has been fielded against Kripashankar. Abdul, who we met campaigning in a slum area of Kalina told us, "I am going to take revenge for the people of the area. You go into any of these lanes - the doors to the toilets are broken, women need a guard outside before they can go to the toilet."
But Mallik himself was briefly in the Maharashtra Navnirman Sena of Raj Thackeray. He claims he was forced to cross over "because of Kripashanker".
Kripashanker Singh however told us that Mallik is unpopular, and NCP workers are leaving in droves to join the Congress.
As with the Sena-BJP, such intense bitterness begs the question: were these alliances ever genuine to begin with?
As senior editor Kumar Ketkar put it, both alliances "were never together really, their live-in relationship was completely false. They never lived in together and therefore there were contradictions between NCP and Congress as well as BJP and Shiv Sena. NCP always distrusted Congress and Congress always thought that NCP is a gang of thugs and they always kept on abusing each other in the rural areas, and therefore NCP and Congress alliance was as bad as the BJP and Sena alliance. Getting out of the alliance for both of them is a happy situation, both of them are now liberated."
Who this 'liberation' benefits, is of course, an open question.