Beat or beaten

No.
The past participle is beaten.

AnonymousCould both be used?

I'd say yes. Of the eight dictionaries I've checked, only the Oxford and the MacMillan dictionaries neglect to list 'beat' as an alternate past participle. Some that include 'beat' are the American Heritage Dictionary, the Merriam-Webster Dictionary, Wiktionary, and the Cambridge Dictionary.

CJ

So, if I excluded the word have in the sentence and only used beat: no one could beat him. That makes it present?

And the use of ' have' makes it in the past?

AnonymousNo one could beat him.

could is ambiguous here without context, but as an isolated sentence, most people would think of the first choice below.

1. was able to (He was such a good player that no one could beat him.)
2. would be able to (If he were just a little faster, no one

When "beat" means "defeat" or "batter," I tend to use "beaten" as the third form.

However, some colloquial idiomatic expressions require that "beat" be used instead:

This has been a long day. I'm totally beat (= extremely tired).

ozzourtisome colloquial idiomatic expressions require that "beat" be used

And conversely, there are some places where only 'beaten' is possible. "beaten metal"

CJ

Ok. So both, 'no one could have beat or beaten' him are past participle? And that is specifically for the word beat. right?

AnonymousOk. So both, 'no one could have beat or beaten' him are past participle? And that is specifically for the word beat. right?

Right.

CJ

What if I said: I don't think you could beat him. Wouldn't that make it in the present?

AnonymousWhat if I said: I don't think you could beat him. Wouldn't that make it in the present?

What's "it"? The main clause? Then yes, the main clause (I don't think) is in the present tense.

If we take the tense of the whole sentence to be the tense of its main clause, then the whole sentence is also in the present tense.

I