A win in Cardiff would see England complete the Grand Slam following Sunday's 18-11 victory over Italy.
However, an eight-point triumph for Wales would give the hosts their second consecutive title.
"Wales will be pretty happy," Sky Sports News quotes Flood as saying.
"They are in a situation now where them winning the championship isn't too far off. We'll be going there as underdogs, they've been playing very, very well of late."
Flood kicked over all of his country's points during their win over the Italians.