When Krillin was fighting Super Buu Krillin knew he couldn't win. But then Babidi used his telekineses power to talk to Krillin and convinced him to put him under his spell.
Power/Strength
Krillin's power increased dramitcaly, Krillin is even a match for Super Saiyan 3 Goku.
Fight with Super Buu
Krillin was fighting Super Buu he was doing really well but then Buu was about to blow himself up, Krillin thought it was all over and he and everyone else was going to die but then he had a vesion of Goku and everyone saying to him not to give up, so he preformed the Destructo Disk and killed Super Buu and saved the day.