Kankavli is now one of the most-watched constituencies in Maharashtra.

The BJP and the Shiv Sena are fighting in an alliance for the Maharashtra polls on Monday, but in one of the state's 288 seats, their candidates are rivals in a fierce battle.

In the Kankavli constituency of Sindhudurg district, Nitesh Rane of the BJP is taking on Satish Sawant of the Shiv Sena.

Mr Sawant was ready to contest as an independent candidate and had filed his nomination too, but he ended up being the Shiv Sena candidate against Nitesh Rane, who had won this seat in 2014 on a Congress ticket.

Nitesh Rane and his father, former Chief Minister Narayan Rane, joined the BJP earlier this month.

Both Chief Minister Devendra Fadnavis and Shiv Sena chief Uddhav Thackeray have campaigned here for their candidates. The Sena is bitterly opposed to Narayan Rane, who walked out of the party even though he was made chief minister.

Kankavli is now one of the most-watched constituencies in Maharashtra.

Chief Minister Devendra Fadnavis said while he was certain that the Sena-BJP alliance will return to power, but in Kankavali, the BJP's Nitesh Rane would win "70 per cent of the votes", leaving the rest (that includes the Sena candidate) for all the others in the contest.

Mr Fadnavis did refer to Rane junior's patchy track record and outbursts of temper; he was on camera earlier this year attacking a government official with mud and slime on a highway near Mumbai.

"I am very happy that Narayan Rane and his entire family have joined the BJP. Whenever there is an issue related to Konkan, Nitesh Rane is very aggressive. Being aggressive is in his nature. Because he has been trained by Narayan Rane. But now he has to come to our school. We don't want to reduce his aggressiveness but we want to teach him the self-control that we have," Mr Fadnavis said.

The Shiv Sena chief Uddhav Thackeray also campaigned in the constituency and did not hold back on attacking Nitesh Rane.

"In spite of the Shiv Sena and the BJP having an alliance, in this constituency I have come because I want the Shiv Sena candidate to win for sure. It does not mean the Shiv Sena and the BJP are fighting again. It's not like the Chief Minister and I are arguing over this. The Chief Minister is a good friend and we have a solid alliance with the BJP. If the BJP had given their own party workers a ticket here I would have campaigned for him. We have made a mistake in the past and I don't want my friends to repeat the same mistakes,"Mr Thackeray said, apparently referring to Mr Rane, who quit the Shiv Sena, joined the Congress and is now in the BJP.

"In 2004-05, Shiv Sena supremo had thrown him out. He did not leave. We kicked him out," Mr Thackeray said.

"At that time the Congress was in the position the BJP is in today. When journalists asked me to react to his move of joining the Congress, I had said I wish the Congress all the best. Now I want to wish the BJP all the best. I am speaking from experience. The Shiv Sena supremo saw through (Rane senior). He kicked him out after knowing what he had done and then the Shiv Sena grew. He went to the Congress and the Congress is now in doldrums. He started his own party. That too is in the doldrums. Now he has gone to the BJP and I wish them all the best," the Sena Chief quipped.

Comparing Narayan Rane to a "demon", Mr Thackeray said, "Satish Sawant has the same bow and arrow that Prabhu Ram carried. When Prabhu Ram killed a demon with his bow and arrow the demon would return in another form. We had a demon in the Shiv Sena and we threw him out. He then went and joined the Congress and we tackled him again. He then started his own party and was defeated. This is his last avatar. This time if we defeat him he won't be able to get up again."

The results of the elections in Maharashtra and Haryana will be declared on October 24.