Lockball tournament held at the 25th of summer month at the east village. Bloom will invite you the day before, so it's almost impossible to miss it.
I'm sure you've already know the controls for playing lockball are, but here it is:
arrow key: movement, tackle
a button/space/keyboard z: kick, lock the goal

1. Already been said in the title, this method does not guarantee you'll beat Paxel or the mysterious player. The last step needs somekind of luck for Paxel not locking his goal. But, I beat him with this "technique."

2. You'll still need to be fast. I compile these steps to make myself be less precise with the controls. Let's be honest, the lockball controls are not perfect. Personal opinion.

3. Some direction guidance: to the left is your opponent, the right is your goal.

4. I thought it will be difficult to explain with words, the steps are shown below with images. So, viewer discretions: graphic content.

5. The opponent in the images below is not Paxel, but let's pretend it is. BTW it's Logan.

6. Nothing to read here. Moving on.

First of all, English is not my main language. This section may confuse you, tell me if anything needs fixing.

1. At the start of the match move your character down to clear Paxel's lane towards your goal. He, almost always, will run directly to your goal. See below:

2. When you're lined with the ball, start moving up until the top end of the field. By doing this, Paxel will jump backwards, giving you space to slid between him and the ball. See below:

I don't know why the image is ♥♥♥♥♥♥ up, but anyway...

3. At this position, Paxel can't do anything. He will stay there until you start to move. The next is to bring the ball to your top bulb thingy that will bounce the ball to your bottom left, but don't let the ball bounce just yet. This is the point, for me, to take a breather because after this is a bit tricky. See below:

4. This step needs a light tap of right arrow, then down arrow, to bring you and the ball to this position:

those light taps need to be fast enough because Paxel could still steal your ball. Immediately follow with step 5...

5. Run your ass off to Paxel's goal (to left, if not clear enough). Just straight ahead. Like an arrow.

Paxel will try to tackle you during your run. Hopefully, you've leveled up your Trickery (Tri) ability so his tackle won't affect you so much. And also kick the ball if you see fit.

6. After you reach the end of the field, immediately move 1 or 2 steps down (I can't remember how much exactly), line yourself with Paxel's top end of the goal and mash your a button/space/keyboard z.

This is the point that needs luck. Paxel could only go down, making the ball goes into his goal. Other times, Paxel will lock his goal, causing the ball bouncing to your behind, which is not ideal. Repeating above steps still possible but a bit difficult due to the ball on your back.

Hopefully, you score a goal:

7. Rinse and repeat:

Defeating Paxel is difficult, but not impossible. Thankfully the AI is simple to beat, you just need to be nimble, agile, and have levelled up your lockball ability.
This is my first guide. I hope this helps someone in need.
Also this doesn't need to be said: save before starting the tournament, and there's no break between the match, so when you lose you can instantly start over.
Peace, yo!