Liverpool are five points behind United with five games left to play and Unittedc also have a game in hand but Riise hasn't given up hope of overtaking the Old Traford side.
We're still hoping for second place, but there's nothing we can do except win all our games and see where it takes us," said Riise.
"The first target is obviously to make sure we finish at least third, but then we're thinking of sneaking second. I know it's going to be tight against Manchester United with only a few games left, but we believe we can do it.
Liverpool require three points to be certain of finishing of third and a win over Blackburn next weekend will guarantee that even Spurs beat Everton the day before. Riise however, believes that the team should focus on their own efforts
If we win our games we're secure so we don't need any favours," insisted Riise.
"At the moment we're playing some good stuff and don't need to think about the results of those below us.
"As long as we keep winning we'll maintain some momentum and keep our confidence up, which we'll need going into the Chelsea semi-final. But the first priority is Blackburn away next weekend."