Guliver said:
Coola said it because Goku was able to survive his eye beam... Coola was weaker than Freeza in his true form.. how is it not contradiction
>after Goku strikes back while saving Gohan
Cooler: "To be able to strike back at me at his position...he just might have defeated Freeza."
>after they tussle in the water, pre-transformation
Cooler: "Hmph, you do as well as I expected. Enough to have defeated by brother. However, the real hell begins now! Once you witness this Hell, I will show you no mercy, no matter how you scream! Not until I've torn you to bits."
It's clear in Cooler's choice of words that his opinion of Goku is gradually getting more favorable. "Might have" -> "enough to have" -> "no match" is a gradual increase in certainty. There isn't a contradiction simply because Cooler hadn't surpassed Freeza until he transformed.