While Dragon Ball's Goku has unlocked god-like powers of his own, he still doesn’t stand a chance against Lord Beerus (aka the God of Destruction) if the two were to ever fight again (considering he lost their first fight), however, there is another Z Fighter who actually could fend off Beerus with one ingenious attack.
Lord Beerus made his debut in Dragon Ball Super Chapter 1 by Akira Toriyama and Toyotarou. In that chapter, Beerus has a vision of someone in his universe rising up and defeating him in battle–a mysterious fighter known as a Super Saiyan God. So, Beerus goes to Earth after tracking down two of the last remaining Saiyans in the universe, Goku and Vegeta, as he hopes one of them is the Super Saiyan God who appeared in his vision so that he can crush them and put his anxieties at ease. After Goku unlocks the form of Super Saiyan God, he fights Beerus, though is soundly defeated by the God of Destruction which eased Beerus’ worries greatly–though it seems he should have been worried about an entirely different, and totally surprising, Z Fighter instead.
In Dragon Ball Chapter 7, Bulma, Goku, and Oolong are traveling the world searching for the Dragon Balls. While Goku and Bulma began this journey together, the two picked up Oolong along the way as Bulma believed his powers of shapeshifting would come in handy during their mission. However, Oolong was secretly plotting his escape as he didn’t want to be involved in the lives of these two adventurers who so recently ended his villainous reign over a small town. Before Oolong decided to make a run for it and leave Goku and Bulma high and dry, Bulma gave him a piece of candy which Oolong unthinkingly consumed. When it came time for Oolong to make his escape, Bulma uttered the phrase, “Pii Pii” and Oolong suddenly came down with a case of violent diarrhea which stopped him in his tracks and kept him from leaving the team.
The candy Bulma gave Oolong was of her own design and once eaten by someone, it basically grants Bulma full control over their bowels for a fairly long period of time. Fans of Dragon Ball Super know that, after Beerus first visited Earth to fight Goku, he continued to return to the planet in order to eat the delicious food Bulma prepares for him. While Beerus is a God of Destruction and greatly enjoys his cosmic task, there is nothing in the cosmos he loves more than food, especially when it’s from Earth. If there ever came a time when Beerus would threaten to destroy the Earth once again, all Bulma would have to do is feed Beerus the candy she gave Oolong, which he would assuredly eat without question. If she says “Pii Pii” this would force Beerus to relieve his bowels and make him have to return to his homeworld in a hurry to take care of his embarrassing situation.
While Lord Beerus is a god, his attention span is incredibly short, so if Bulma used her diarrhea-inducing candy to make him flee before he destroyed the Earth, it is likely he wouldn’t remember wanting to destroy it. If Goku tried to fight Beerus again in an effort to save the world, Beerus would destroy him and the Earth without breaking a sweat. However, if he was forced to leave in a hurry as he would if Bulma gave him her special candy, then the Earth would be saved–meaning Bulma is the only Dragon Ball fighter who can beat Beerus, not Goku.