Williams was the starting striker for Haladas again after a fine performance on his first start last week.
It didn't take him long to reward manager Geza Meszoly's faith, netting in just the 2nd minute of Sunday's (AEST) match at Sopron's Kaposztas utcai Stadion.
Haladas' Mario Nemeth extended the lead after 21 minutes with a fine chip, and moments before half-time Williams assisted teammate Barnabas Racz with the final pass on a quick counter attack to go into half-time 3-0.
Zoltan Liptak pulled one back for Diosgyori in the second half, but it proved to be no more than a consolation goal - 3-1 the final score.
Back-to-back wins have put Haladas into 6th place in Hungary's OTP Bank Liga table.