Other source:
Now at full strength, the battle between Goku and Pikkon really heats up. The stadium is rocked with their awesome power. Since they seem evenly matched, Pikkon reveals his greatest technique: the Thunder Flash attack. Goku is flattened by this powerful blast twice. But when Pikkon decides to use it a third time, Goku finds a weakness. He uses Instant Transmission to appear right behind Pikkon and delivers a Kamehameha wave that blasts him out of the ring. It seems that Goku has won, but the Grand Kai reveals that both Goku and Pikkon touched the ceiling, which disqualifies them both. As a consolation, he offers a private lesson to both of them in 200 years.
