To reach Level 10 you'll need to earn a total of 19 Stars.
The following is a list of all challenges and the requirements to beat them:
One Star Challenges
Trigger a x2 multi-ball
Really simply. After you've hit the first single ball four times against the back panel, it'll split into two.
Hit 15 balls in one game
Again, this is really easy. Hitting the same ball multiple times counts. You should get this with the first 30 seconds of the game.
Do an upward swing to hit a fast ball
As the title says - Do an upward swing. Doing so will speed the ball up and cause it to be a "fast ball".
Return the ball to the mascot twice - Cumulative.
This only unlocks by playing two games. Simply return the ball back to the back panel right at the start. Then repeat in another session.
Reach a score of 20
You should reach this with ease. You can do it with one ball or multiple, it's up to you. Just make sure you hit a score of 20 before you lose.
Keep 2 balls in play for 5 seconds
A second ball will be introduced at 4 hits of the back panel with one ball. Once there's two, just keep an eye on the colours and keep them active for 5 seconds.
Do a downward swing to hit a slow ball
Do the opposite to the upward swing and swing downwards. Kind of like slicing the ball. Doing so will turn it into a "slow ball".
Return 2 balls at the same time
This is a little luck based. You'll first need to have two balls on the court and then hope both bounce back the same way. Move your hands into position and hopefully they'll hit the racket with a split second or so of each other.
Play a single game for over 30 seconds
This shouldn't cause you any issues. Simply keep the ball(s) in play until the challenge unlocks. If having multiple balls in play is proving to be hard, let a few pass by.
Hit a total of 100 balls - Cumulative.
Simply just keep playing and this will unlock.
Return a red, then a yellow ball
This should come naturally. The first ball thrown will be red, and when it splits into two, the second will be yellow. With a bit of luck, the red will come back to you first followed by the yellow.
Return a red and yellow ball at the same time
Requires a bit of luck, but very similar to the above challenge.
Trigger a x3 multi-ball
To reach a x3 multi-ball you'll first need a x2 multi-ball on the court. Once you've got two balls on the court, get five returns to split one to obtain a third.
Reach a score of 55
You should reach this quite early on at the start of a game. Don't miss any balls and about halfway through the x2 multi-ball you should get the score.
Cross your arms to hit a red and yellow ball at once
Again, luck based. Once you hit a x2 multi-ball, one will be red while the other yellow. Simply wait and hope that the red heads left while the yellow heads right. If so, cross your arms and hit both balls to complete the challenge.
Pass a score of 40 while on a x2 multi-ball or higher
This shouldn't be too hard. You can reach a score above 44 with a x2 multi-ball, but if you manage to reach a x3 you'll get it no problem.
Return 30 balls in one game
This will most likely require you to get up to a x3 multi-ball. Once you reach that and you don't miss any, it'll come fast. If x3 is proving hard, let one ball pass and continue with two.
Return 2 red balls at the same time
Same as the other return challenges, this will require a bit of luck. You'll probably have to get to x3 multi-ball to have a chance of having three red balls no the court.
Hit a total of 40 x2 multi-balls - Cumulative.
As stated, this is cumulative over all your games. So simply keep playing.
In one game slow down 2 red balls and speed up 2 yellow balls
Fast balls you swing upwards and slow balls you swing downwards. To get this out of the way fast, do the fast balls right at the start on the first ball. Then when it splits into two, do the downwards movement on the yellow as soon as you can.
This way you won't have to worry about having a lot more balls on the court and getting confused at what one is where and losing your game.
Reach a score of 100
Simply concentrate and keep an eye on what colour is where. Having more balls on the court at one time will make it go faster, but may prove harder. If it gets a little too frantic, lose a ball or two and concentrate on the ones you have.
Hit 40 balls in one game
Same as above. More balls will make this go faster, but if it's proving to be too hard, let a few pass.
Pass a score of 60 while on a x2 multi-ball or higher
By the time you get around 60 points you shouldn't be on a single ball. By this time you should be on x2 if you're trying to slow the game down or at least x3.
Hit a fast ball, then slow ball, then fast ball
Do this on the very first ball. As soon as it gets to you, do an upwards spin. Once it returns, follow up with a downwards swing and then finally another upwards.
Two Star Challenges
Hit 4 fast balls in one game
Real simply. Do an upwards spin on the very first ball and you'll get this within seconds.
Play for 20 seconds without dropping a ball
This challenge will unlock while you're one a x2 multi-ball. Playing the game for 20 seconds shouldn't cause you any issues.
Hit 7 yellow slow balls in one game
The best way to do this is on the first yellow ball you get when you first get the x2 multi-ball. If done right, you should get between 4/5 slow balls (downward swing) before you hit the x3 multi-ball. If x3 is proving too hard to get the last slow balls in, let one pass by you.
Trigger a x3 multi-ball without losing a ball
You'll need to get a few hits to get a x3 multi-ball. Four at the start, then five returns on the x2 multi-ball. After you've done that, a third ball will be introduced.
Trigger a x4 multi-ball
Once you trigger a x3 multi-ball, hit each ball five times in a row to trigger the a x4 multi-ball.
Play for 40 seconds without dropping a ball
Simply play for 40 seconds without missing a shot. If you are finding it hard with the multi-balls on the court, try and use slow balls or let some pass by.
Play a single game for over 60 seconds
Very similar to the other time based challenges. Slow the balls down if possible or left some pass by you to have less on the court.
Hit a red and yellow ball at once 3 times - Cumulative.
This is the same as the one mentioned above, but you just need to do it three times. Note that is not all in one game, even though you should get it in one.
Keep 3 balls in play for 10 seconds
Once you reach the x3 multi-ball, just concentrate on the coloured balls. In most cases and for a fair few seconds after the x3 split. The red ball(s) should bounce back to the right and the yellow ball(s) should stay to the left.
Trigger a x3 multi-ball twice in once game
Really simply way of doing this. Get to the x3 and as soon as you can, let one of the balls pass. Now return the x2 five more times to split them again and the challenge will unlock.
Hit a total of 200 balls - Cumulative.
Simply keep playing the game and this will come naturally.
Hit 1 fast ball, then 2 slow balls, then 3 fast balls
Again, do this right at the start. You should get this just as you hit a x2 multi-ball.
Reach a total score of 450 - Cumulative.
Simply keep playing the game. If you can get this if you play by the third game you play if you get some good scores.
Return 75 balls in one game
Repeat what I've mentioned above. Having more balls on the court will help and make this go faster! If it gets too busy, let a few pass.
Perform a total of 40 fast balls - Cumulative.
Again, just keep playing the game. If you swing upwards for each hit, you'll get this in no time.
Three Star Challenges
Drop down from x3 multi-ball to x1 and keep scoring
Keep playing until you reach a x3 multi-ball. Once you reach it, simply miss two balls on purpose but make sure you save one and get the return.
Hit 10 yellow x3 multi-balls in one game
This shouldn't prove too hard. As mentioned above, the balls have a set return side once and while when you hit a x3. If you get a x4, make sure you let a single ball pass.
Trigger a x4 multi-ball without losing a ball
With the amount of balls bouncing about on a x3, this should come quite quickly as long as you keep your concentration and don't lose one ball. If you miss a ball, you'll have to restart the game.
Hit a total of 50 x3 multi-balls - Cumulative.
Again, this is over the course of all the games you play. So keep getting to a x3 multi-ball and return as many as you can.
Play a single game for over 80 seconds
1 minute 20 seconds can feel like forever. I'd suggest you try and keep to a x2/x3 multi-ball. Lose a ball or more if needed to help slow the pace of the game down. Remember to no hit a any balls as well, just let them bounce off the racket. As soon as you hit the required target time, the challenge will unlock.
Hit alternate fast and slow balls for 4 hits
This one can be a little tricky. Sometime the up/down motion swings does not always register. You can get this on the very first ball but for me it wasn't unlocking. I didn't know if I had to do it with two balls, different arms etc as it just didn't work.
I then did it on alternating from fast to slow with one red and yellow ball and it unlocked. Now I don't know if this was luck and it just wasn't registering with the single red ball or not. My guess is, the swings weren't connecting. So do this on the very first ball.
Hit 15 red x3 balls in one game
You shouldn't have any issues with this. As long as you hit all red balls presented to you at the start of the game, you'll get this by about the x3 multi-ball.
Return 50 yellow balls in one game
You'll need to be on around x3/x4 multi-ball to have a chance at reaching this limit in one game. Doing so, you'll have more chance of yellow balls being on the court at one time. Going any lower on the multi-ball chain will just make things hard and slower as the score increases.
Hit 10 fast balls in one game
You can get 4 from the first ball without any issues. Once you get the x2, you can get the remaining 6. Just remember to do the upwards swing.
Reach a score of 100 without dropping a ball
Hopefully you're good at the game by now... You're going to have to reach a x4 multi-ball for this. There's no way around it, seeing as you're not allowed to miss a ball. Make sure you keep an eye on what's coming back at you and not what's going away after each return. Doing this will make you miss a ball or two.
Play for 60 seconds without dropping a ball
Not as hard as the 80 seconds. Follow the tips I've typed for that challenge and use them for this.
Hit 30 yellow and 30 red balls in one game
Like all the other challenges similar to this, you can either do this the fast way and get to a x4 multi-ball or take it slow by transferring between a x2 and x3 to keep the pace nice a slow.
Keep 4 balls in play for 15 seconds
Hopefully your reactions are good and fast. 15 seconds may be short but trying to keep 4 fast balls on the court is a little tricky. Not much advice I can give, other than what I've mentioned for other similar related challenges.
Reach a score of 200
By this time 200+ should be the scores you reach when playing a good full game. The score will increase a lot faster when you have more balls on the court. So aim for the x3/x4 multi-balls.
Return 2 red, then 2 yellow, then 2 red in order
A bit of luck is needed here. Only advice for completing this one is to let the colour you don't want to hit pass by you. Unless it's the last one of course. Just remember what you need to hit next and keep one arm down by your side so you don't hit the wrong ball by mistake.
Return 20 red fast balls in one game
Really easy for a three star challenge. For every ball, just keep swinging upwards. If things get a little too fast, either let some pass or turn them into slow balls. You should get this quite fast if done as much as possible.