No character in One Piece is beating these two together (besides maybe Imu), they have been depicted as formidable opponents for even the likes of Prime Roger and Whitebeard. The close bounties alone are a good evidence.
@ninelven: Nothing is given yet bro. Wait until it happens before you count it towards a character winning or losing. And I'm personally not convinced that Zoro and Sanji are stronger than G4 luffy from Dressrosa arc. Doffy also had his guts sliced up by law before luffy even fought him in G4.
Doflamingo stitched himself though, he was weakened, but that that much.
If current Zoro and Sanji were not at least on par with Dressrosa Luffy despite all the power-ups since then (physical and Haki progression, Enma and Raid Suit) the Monster Trio dynamic would be gone.