Brazilian Portuguese has some phonological differences that I think confuse people in both directions more than other varieties of Portuguese, like the /tʃ/ and /dʒ/ for <t> and <d> in various contexts. For example a Spanish speaker would probably have a hard time recognizing that Brazilian Portuguese /dʒi'abu/ is cognate with Spanish <diablo>. A Brazilian Portuguese speaker who was less familiar with Spanish might similarly have a hard time recognizing /ˈdjablo/ as cognate with Portuguese <diabo> 'devil'.

Or Brazilian /'sedʒi/ is cognate with Spanish <sed> 'thirst'. A Spanish speaker will have to know to effectively ignore the /ʒi/ in order to recognize the word easily!

Maybe more extreme, Brazilian /'hedʒi/ (written <rede>) is cognate with Spanish <red> 'net, network'.

You might also be familiar with a greater variety of Spanish pronunciations as a non-native speaker... if you know Argentine /'ʃubja/ and /'ʃabe/, then you have a better chance to recognize Brazilian /'ʃuvɐ/ and /'ʃavi/ ('rain' and 'key', respectively).