Galen Marek vs. Darth Maul (sabers)

Battle takes place next to Bane's skeletal remains.

Maul.

Galen Marek handled Darth Vader in TFU.

I wouldn't say Galen was more skilled than Vader, though; he played on his temper to provide an opening. Even if he were more skilled, though, that's not really concrete proof that he could defeat Maul, either.

I'd probably give it to Maul.