I meant Bakugo propelling himself is faster than Gravattack's reaction, which leads to him getting very close (the distance is only 20 meters, is very close), Gravattack stops him and as he throws him, Bakugo shoots with an explosion that would also be faster than Gravattack's reaction, leading to him being able to hit him (stronger than Gravattack's durability), this makes him pause for a moment and Bakugo quickly zooms in and attacks with everything he's got (AP Shot Auto-Cannon, for extra speed or a big blast ), having a chance to win
All of this relies on Gravattack not starting to increase gravity at one point, which it doesn't usually do, preferring instead to launch people or things.