Two of the Premier League's outstanding goalkeepers go head to head on Sunday when European hopefuls Portsmouth and Blackburn clash at Fratton Park.
"I rank both of the keepers up there as among the best in the league and they are going to be a huge part of the game on Sunday. They could determine which team comes out on top," Emerton said.
James, 37, has reclaimed his international place thanks to another outstanding season for FA Cup finalists Portsmouth.
But Emerton would not swap the England man for Friedel, who at just 12 months younger than James is still at the top of his game after eight years at Ewood Park.
"It's great to have Brad behind you," added Emerton.
"As I've said before I rate him as one of, if not the best, keeper in the league at the moment and I think he has been for many years now.
"It gives the back four and the entire team huge confidence to have such a great goalkeeper behind them."