But Goku wasn't shown overeager and your answer really doesn't explain why Goku bother to asked if Black could floor him.
Goku had no tactic other than the Evil Containment Wave to seal Future Zamasu. When that failed, he had no issue with just beating Black up. Nothing supports that he was 'delusional'.
Goku melted half of Merged Zamasu's face. Vegeta didn't even with Trunks help. That's a far greater feat than Vegeta beating up Black. So Goku is shown to be stronger than Vegeta.
His clones were able to hurt Vegeta when he couldn't before. He even told Vegeta and Goku to get stronger, which is why he sent Zamasu to kill Future Trunks and the others.
You were thinking manga since you claimed that Black had to retreat since he was weaker than Vegeta, which wasn't the case. Also, the director of Super outright called the strongest character Beerus, not counting the fusions.
That fact that he was actually suggesting he could take on Black is showing that he's overeager, considering what happened in the past episode. Either that, or he actually did have another strategy. (Which wouldn't take away my point about Vegeta's SSB being stronger than Goku's)
What would make him delusional is the fact that he had just lost out to Black in raw power 2 episodes ago. I was suggesting maybe he had thought of another strategy aside from Mafuba.
Yeah, I know, and I already pointed out that as being a weird moment considering it was just established that Goku was weaker than Black in terms of raw power prior to that. Before that point, it is only reasonable to assume Vegeta's SSB was stronger than Goku's SSB considering Vegeta started wrecking the same guy that overpowered Goku.
Vegeta getting hit by a technique doesn't mean Black was stronger than him in raw power. There's no way to prove at that point if Vegeta was actually weaker than Black considering their fight didn't continue.
I was thinking of the anime. My argument about it is that he had to retreat back with Zamasu. Though I can see the confusion. I mean to say that Vegeta had the advantage in raw power until he left. (Retreat can simply mean withdraw) Even after Black's anger power up, Vegeta still dodged his scythe attack with ease and it was only the clones that had them held up, but even that doesn't mean Black was stronger.