|Mondeville out-rebounded Pecs 40-32|
Williams poured in 30 points to make the difference in a key clash between two teams who entered the night at 1-1 and needing to make a move to keep up with the group leaders.
Kristen Sharp also came up big at both ends, with 13 points and 12 rebounds for the victors.
Mondeville wasted little time in taking control of the game, with a 16-2 first-quarter burst, which included nine points from Williams, putting them 18-5 up with less than six minutes gone.
Pecs would cut the gap back to five, 34-29, on Zsofia Fegyverneky's jump-shot late in the second quarter, but they never got any closer even though they would twice more get the gap down to that margin.
Williams stuck around to finish what she started, scoring the final points of the game with a three-pointer 39 seconds from time.
Alexandria Quigley led Pecs with 18 points and 10 rebounds, while Fegyverneky had 12.