"I expect Northern Ireland to play with a similar structure to what we saw in Porto... they are aggressive and play direct football," Sky Sports News quotes him as saying.
"They have got quality and maybe I expect them to take on the match a bit more than last time. Northern Ireland have a chance, so maybe it is possible that they attack a bit more."
Northern Ireland also defeated Russia 1-0 last month, a result which Bento believes should serve as a warning to his players.
"The Russia match was another warning. We knew this match would be tough but that game and the way they beat Russia showed that they're a really strong squad. It was a warning for us," he added.
Northern Ireland take on Portugal tomorrow evening at Windsor Park.