Round 1 - Rita is Loki's superior in every single way aside from illusion magic I guess. She takes this easily.
Round 2 - Goldar should win. Firstly, he's several hundred times larger than Destroyer. Secondly, Rita amps him when she fuses with him. Third, the Megazord showed sufficient strength to b*tch slap Rita into space. It wouldn't be too hard for Goldar to replicate the feat or at least to BFR.