I will revenge them about their play of last week.

I will get my revenge for their play last week. or I will avenge my loss to them last week.

My play was not good last week because I was tired. I did not play well last week because I was tired.

Or, 'I did not play well last week because I was tired.' If 'play' is the subject, use 'good.' If 'play' is being described by an adjective, and the sentence starts with 'I,' then use 'well.'

So I am keeping my condition and feelings strong until tomorrow.

I am determined that I will not make the same mistake as last week.

I will play tennis with my friends; one of them is impolite and does not have a good personality.

However, I will not lose to them.

If they do silly things, I will return and attack to them through my play.

I will get revenge on them for their play of last week.OR 'I will avenge my loss to them last week.'