Actress Moon Moon Sen Friday pulled off a a major upset on debut by defeating nine-time MP Basudeb Acharia of the CPI-M in West Bengal's Bankura Lok Sabha constituency.Trinamool Congress nominee Sen triumphed by 97,511 votes over Acharia, who has been winning from the seat without a break since 1980.Sen, daughter of Bengali screen legend Suchitra Sen, received 481,911 votes. The 71-year old Acharia, leader of his party in the outgoing Lok Sabha, managed only 384,400 votes.