Senior Congress leader and party's campaign chief, Narayan Rane, was trounced in his home constituency of Kudal in Maharashtra's Sindhudurg district on Sunday.
He lost to his main rival, Shiv Sena's Vaibhav Naik by over 9,000 votes.
Fellow Congressman and chief minister till last month, Prithviraj Chavan, is engaged in a neck-and-neck contest in Karad South with the seven-time sitting legislator Vilas Undalkar.
Former home minister and NCP leader RR Patil was also in a tough fight in Tasgaon. Former deputy chief minister and NCP leader Ajit Pawar was leading in Baramati.
The ruling Congress and NCP parties looked set for major setbacks in the Vidarbha region with outgoing ministers, Anil Deshmukh of NCP, Nitin Raut, Rajendra Mulak and son of PCC chief, Manikrao Thakre, Rahul Thakre, all trailing from their respective assembly constituencies.