It's safe to say that maul even as of TPM would win. Seeing as maul was essentially off his rocker in an unground cavern for years and years not doing anything but being crazy, it's safe to assume he didn't improve much between TPM and his return in the clone wars. Maul schooled Opress in their little scuffle so I don't think Opress could win under any normal circumstance.
Originally posted by TheOneOfMortis
Yeah if anything he ould have porbably got a lot worse.I havem't been keeping up to date with the cartoon though what exactly has Maul done combat wise since his return?