Bale has scored three stunning set pieces in his last two matches to help Spurs record victories over Newcastle United and Lyon, and Friedel had sympathy for opposing goalkeepers trying to stop the Welsh winger from scoring.
Friedel told reporters: "He has been working a lot on his free kicks – he is perfecting that style. And I tell you, it is so difficult to save. It is such a difficult ball to deal with. It's great for us that he has that in his repertoire.
"If you set your wall up correctly, you see it come off the foot, then you have to react to the first direction that it goes.
"And the problem is that there's no spin on the ball, the way Gareth hits them. So if there's no spin on the ball and then mid-flight it goes the opposite way, there's no way to train your eye to deal with that. You just have to react the best you can."
Bale has scored 17 goals in 30 appearances for Spurs this season.