Of the five Assembly constituencies, four at present are held by the Congress-led United Democratic Front (UDF) and one by the state's ruling CPI-M-led Left Democratic Front (LDF).
While State Congress President Mullapally Ramachandran insists it would be 5-0, the LDF is optimistic of retaining not just Aroor, but also wresting Vatiyoorkavu and Konni from the UDF.
The BJP, which has just one member in the 140-member Kerala Assembly, is hoping to add to its tally, but exit polls predict a blank for it.
Though heavy rains on polling day marred the voter turnout (just 57.90 per cent) in Ernakulam, the Left is hopeful of independent candidate Manu Roy doing the magic for the party. Roy is supported by the LDF.
The Congress is also keeping its fingers crossed in Vatiyoorkavu, where Chief Minister Pinarayi Vijayan campaigned for young Thiruvananthapuram mayor V.K.Prasanth and many believe he may have swung the vote in his party's favour.
However, senior Congress leader Ramesh Chennithala, who led the UDF campaign, tried to avoid a guess. "Everything is in the box, so there's no need to make any more predictions," he told reporters when asked about Vatiyoorkavu.
Insisting that exit polls can go wrong, parties point to predictions of a UDF victory in last month's Pala Assembly bypoll, when the Left actually wrested the seat after 54 years. Whatever the outcomes, it is testing time for both Vijayan and Chennithala.
( With inputs from IANS )