Dude, think about it.
Lee can open the eighth gate, okay. And the 8th gate surpasses Kage level. Okay.
It doesn't mean that the 8th gate can surpass the strength of FIVE Kages working together. Hype don't mean crap, give me proof.
Madara has the EMS and rinnegan, and even if we don't say he has the Rinnegan or Mokuton, okay, he still has the EMS.
He still has perfect Susanoo and can create Shadow Clones WITH MORE PERFECT SUSANOOS. Sasuke could see with 3 tomoe the path of Naruto's strikes, Madara sure as hell could be able to see the path of Lee's strikes no matter what.
Madara has Susanoo, so he has to have Tsukyomi. All Madara has to honestly do is look at Lee and Lee is done for. Lee would have no way of disrupting his chakra flow or hurt himself, so he has no way of getting out.
Madara is way too smart, too strong, and has way too much at his disposal to have it even be considered a contest against Lee.