Defoe feels they're better than their table position suggests.
"I think Southampton are a good side with good players and they move the ball well," Defoe told the club's website.
"I watched them against Manchester United and although they lost that game, for the first 20, 25 minutes they were unbelievable.
"I can remember playing at St Mary's a few years ago, it's a lovely stadium and it will be rocking.
"It will be a tough match but I can't see why we can't go there and get the three points."