(Tale 25)

Krillin can be a little underhanded and sneaky. No time was this more apparent than when Kamesennin threw a stone with the turtle mark into the jungle as a training exercise to see who would become his pupil. After Goku found the stone, Krillin snatched it away and ran like the wind to try and claim victory for himself.

(Tale 29)

Krillin braved the Kame School's harsh training together with Goku, becoming much stronger and eventually entering the 21st Tenkaichi Budokai.

(Tale 30)

During the preliminaries, Krillin was able to prove just how strong he'd become when he sent one of his former bullies from his days at Orin Temple flying out of bounds with just one kick.
In his first match of the main tournament, Krillin found himself reeling from Bacterian and his wretched body odor. That is until Goku reminded Krillin he doesn't have a nose to smell the putrid stench with, allowing Krillin to claim victory over his gargantuan opponent with a stink bomb of his own.

(Tale 35)

In his subsequent match, Krillin faced off against Kamesennin, who was disguised as a fighter named Jackie Chun.
Despite Jackie's overwhelming strength, Krillin managed to briefly gain the upper hand by distracting the old lecher with a pair of girls' panties.
He used the opportunity to land a kick that sent his opponent flying out of the ring, but Jackie propelled himself back in bounds using the Kamehameha and defeated Krillin with a devastating blow.