I highly doubt Sanji's leg is that hot to turn Croc into glass and that he could even hit such a high volume of sand with his diable jamble.
If Sanji can have a constant water supply like Luffy, except indestrucible, then Sanji wins. Luffy would need G2 to beat Sanji here, whereas he didn't need G2 against Crocodile.
If Sanji has no water then Croc obliterates him. He obliterates Zoro while he's at it, until Usopp or Nami comes to save them.