In the manga it is made clear that rematches are clear for FT.
We all saw how Hakume instantly defeated Natsu and Gray at the same time, plus it was super easy.
The rematch was with only Gray, and we all know how it ended.
This example doesn't seem to work for Erza on this forum.
We all watched as Suzaku defeated Erza and Natsu, Erza being behind the group and being the only one to react (not Natsu).
Erza protected the group, she didn't expect that attack, instead Natsu was totally enraged and made an absolute fool of himself, since he couldn't even react to the attack, he being the one who was going to attack.
The rematch ended in a draw with Natsu, with him still unable to see Suzaku's attacks.
Natsu trained and prepared, but because people on this forum can't think that Erza doesn't train, this is ridiculous.
Furthermore, she was convinced of FT's victory over Diavolos, and knowing Suzaku's strength.
Erza knows the power and speed of Suzaku and she looked victorious, she was prepared for the fight.
If Natsu can prepare, then Erza can too, and they both did, they both faced BDSK and proved to be on their level.
Erza was able to surpass an equal to Suzaku, said by Selene, the Diavolos trio and Suzaku himself.
And it seems thay people take Selene's words seriously, it have to remember that Selene is a liar.
It must be remembered that her fight with Suzaku was a lie so that she would take him prisoner to the guild so she could kill Geor.