After a 0-0 game through nine innings, the Whitecaps surrendered two runs in the top of the tenth before Reynaldo Rivera hit a two run home run in the bottom half of the inning to tie the game back up.
Beloit was able to scratch across a run in the 12th inning to ultimately take 3-2 lead that held for the final score.
Joey Morgan led the Whitecaps with three hits on the night while starting pitcher Dane Myers picked up a no-decision, allowing five hits and striking out two in six innings of work.
The Whitecaps are now 47-48 overall on the year and 11-14 in the second half, six games behind first place Bowling Green for first place in the Midwest League Eastern Division second half standings.
The Whitecaps will next travel to Kane County where they begin a series on Wednesday at 7:30 p.m.