Pretty interesting idea. Adding some pauses between rounds to avoid constant streams of consecutive wins would be nice (especially against a CPU opponent who just instantly goes for the ball as soon as a match starts... and before you can react), and shortening sounds would help reduce some of the excessive noise. Overall, I think that I couldn't get super into the otherwise interesting base of a gameplay loop because the sounds, small UI, and quick match starts (and lack of pauses) made it difficult to follow.
Also making clearer exactly what isn't alright to touch (the goals and stuff, especially) would make it more accessible right off the bat. :)
Nice colors, sprites, juice and sound (with the long "LET'S GO" overlapping a bunch, as mentioned above as an exception).