Wasps travel to nearby Oxford for the second meeting between the two sides in the league, with Southwell's men having come out on top at home earlier in the season.
"What they have done so far this season is a huge credit to them and their key strength is how they trust each other on the pitch in attack and defence. They bring a real hard edge to the breakdown so we know it's going to be massively physical and they have a good record at the Kassam so we appreciate this is a really tough one."
Wasps go into the game on good form with just one loss in their last six games, but an away win in the league continues to elude the side, having not done so now in over 12 months.
"That away win is one we are obviously desperate to get now at this stage," Southwell added.
"We are an improving team but we are not quite there yet in terms of being consistent throughout whole games and when you are away, if you make those little mistakes you get punished. Most of the games we've lost this year have been by around three to seven points so you could say that we are very very close but still it's frustrating to be far away as well. We have another chance this weekend but we need to be more consistent."
Sitting seventh in the Aviva Premiership table, Wasps are now just five points shy of their total tally last season, but Southwell isn't about to start celebrating.
"You can't really sit back and assess the season yet and you can't really say you are happy with seventh but we can be happy with how much we are improving. We all want to be higher up the table and we believe we can do that but I don't think just yet you can make any predictions. We will have a far better idea at the end of January where we are as we have some huge games in the league, in Europe and in the LV=Cup to come in the next six weeks or so."