It's because of their teamwork. Take Law out of the equation, Luffy would be decimated. Take Luffy out of the situation, Law would be decimated.
Yeah sure, getting your organs shredded apart isn't gonna slow you down whatsoever. Whatever you say.
He didn't need Trebol at all. Trebol has barely done anything in this fight.
Nope. It wasn't until Law hit Doffy with Gamma Knife that Luffy was able to even land a blow on Doffy on his own. Before that, Doffy was dodging all of his moves and beating him.
I disagree. Vergo was portrayed to be much stronger than Pica, so I don't think Zoro would defeat Vergo so easily.
Or Doflamingo restrains Zoro/takes control of him and defeats Luffy.
All you do is make any speculation based on what makes Law look good.
There is no reason to believe that Vergo was vastly more powerful than any of the executives other than what you want to believe.
And it has been repetitively stated that the Executives are Doflamingo's strongest men.
And Pica was able to completely reshape the island, Zorro beat him using rapid mountain cutting slashes, that is beyond anything that Vergo ever showed, so there is more evidence that Pica is stronger than Vergo than otherwise.
Also Doflamingo wasn't using his King's Haki against Law and Luffy, until Luffy directly confronted him so he has been holding back.
Also its impossible to dodge at close range, Luffy and Doflamingo were nose to nose, so there is no reason to believe that Law's attack helped there other than, once again, your desire for Law to look good.
And most importantly the main villain never goes all out until the last chapter or two of the fight, so Doflamingo is still going to use his full power and best attacks against Luffy, and like always Luffy will overpower these attacks and beat him.
Or are you going to try to claim that we will never see Doflamingo go all out or that Law's attack was so powerful that Doflamingo will tip over any second and that the author will give us a cheap and anti-climatic ending solely to make Law look good.