Rental property closing was on 12/31/2020; file in 2020 or 2021 tax return?

We closed on our first rental property on 12/31/2020 (ie, only 1 day of rental income to report and claim deductions [mortgage interest, insurance, property taxes] or deduct expenses from).

Should we wait to report the property in our 2021 taxes and deduct expenses including closing costs?

Or do we file in 2020 and the closing-cost expenses will carry over?