The sides have been involved in two close finishes in the Guinness Premiership already this season.
An injury-time try gave Bath a narrow win at The Recreation Ground in November while two Tom Croft tries helped Tigers come back for a victory in the reverse fixture at Welford Road in January.
England international fly-half Flood says he expects Saturday’s game at the Walkers Stadium to be another hard-fought encounter.
Flood said: “I think the teams are pretty well matched. We got close to snatching it down there and they would say the same up here.
“It’s been difficult in terms of trying to split the two teams apart. That’s the exciting thing about cup rugby, that anything can happen.
“The way the guys have played against each other in the past, it’s obviously before my time, but it is always something the fans and the players have enjoyed.
“It’s important for us to put a good performance up and to enjoy the occasion as well.”
Tickets for the game remain on sale by calling 08701 28 34 30, or by visiting the ticket office at Welford Road.