See the 2nd ring, it signifies the same sound as that of metals clashing, or the clashing of haki. King used haki, and Sanji used haki to block while he is busy grabbing and saving Momo
yet Luffy points out in PH how Sanji is one of the three capable of haki in the crew, yet we're supposed to believe he didn't use haki when Vergo was capable of trolling his ass. Sanji used haki and Vergo still shat through it