Worst-case rhymes with:
caisse, case, cayce, encase, incase, ace, apace, arianespace, base, brace, caisse, case, cayce, chace, chase, crace, dace, debase, deface, disgrace, displace, drace, efface, embrace, encase, erase, face, frace, glace, grace, heyse, incase, interlace, jonbenet's, lace, left-brace, mace, misplace, nace, pace, place, race, rais, replace, retrace, right-brace, space, trace, vase, wace
Worst-case sounds like:
workdays, workouts, worksheets, wright's, wrights, wrists, wristwatch, wristwatches, wursthaus