Which sentence is correct?

Well I think bobsal was having fun with the word "correcteror." So I followed suit and joined in the fun with my own non-word.

They're both correct. The thing is, we'd need to compare them to the way the entire text is written. Separating the thought into two sentences can be a way of imparting a sense of irony which might be effective but we can't judge it in isolation. Context is an important factor which is often left out of usage questions.

A good rule of thumb is that a sentence makes sense on its own. Hightor does have a point about style, but in the absence of rhetoric and other devices it's best to look at it as a stand alone sentence.

Boxing no doubt offered Bruce Lee a challenge.

This makes sense on its own. If you read it out of context you still know what's going on.

Boxing no doubt offered Bruce Lee a challenge, as it did to Gary Elms.


This also makes sense on its own.
Many thanks, izzythepush!

As it did to Gary Elms.

This makes no sense on its own, it's completely dependent on what precedes it.

Therefore, Boxing no doubt offered Bruce Lee a challenge, as it did to Gary Elms. is correct.