Luffy was able to take on Z and we still don't know the full extent of his new powers and abilities. We don't know if Luffy could at least hold off an Admiral yet. Not defeat one, but at least hold his ground.
This would have been my answer:
@Monkey:
Yes in that non-canon movie, right.
And even then Oda added that he could only beat him because he was a former Admiral. He must have been out of shape (and well, that wasn't much of a defeat if the guy could still go against Kizaru and the Vice Admirals, IIRC. Plus, the battle was so out of character…).
I think that Luffy could at least hold off an Admiral for a bit. I'm pretty sure that Lucci was stronger than Luffy and more skilled. Luffy just had more willpower and an emotional drive.
A bit…5 seconds? Or 7? Yeah, he'll last some seconds more than he did pre-skip :D
Lucci was a tiny-bit stronger, the difference was not as high as it is between Luffy and an admiral level opponent. I'm not saying this because I want Luffy to be a weakling, it's just how it has been portrayed in the manga. As long as Dofla fears a Yonkou and doesn't even bother to try something against Kuzan, you can forget Luffy to even be able to stand against such an opponent for a few minutes (the same goes for Law, will be interesting to see how he gets out of the current mess).