Rovers goalkeeping coach works with the big American on a daily basis and no one needed to tell him what the man is capable of.
"Brad is your typical all-American athlete but I think he has probably got the longest arms in football," said Tunks.
"He is just a terrific athlete, has a great spring, good hands and everything about him is class."
But for all those attributes it is the 29-year-old's temperament and metal strength that Tunks believes sets him apart from the rest.
"He has got a brilliant temperament and mental attitude," he claimed. "In a lot of ways all the top keepers are the same in terms of ability, what sets the best apart is that they have got great presence.
"Brad keeps really calm under pressure and if he has to make 50 decisions in a match, 48 of them will be right. For the top keepers in the first and second division, they might only get 43 right, that is the difference."
One decision Friedel certainly got right in Cardiff was the save at the feet of a rampaging Les Ferdinand with the score standing at 0-0.
"That was pure class," said Tunks. "He showed how quick he is across the ground and I was delighted when he decided to try and take the ball round him. His reach and spring were superb. Ferdinand thought he had beaten him and I think a lot of others did as well.
"Brad was superb that day but he has been ever since Graeme brought him to the club. The manager has a great belief in him and that is deserved."
But Tunks is keen to point out that Friedel is just one of several quality keepers he has worked with at Ewood Park since he was brought to the club by Roy Hodgson five years ago.
"I have been really lucky because I have worked with some really good ones," he said. "Tim Flowers, John Filan, Alan Kelly, Alan Fettis and Alan Miller are all internationals and there has been a great spirit among them all.
"It really is like a club where everyone works together and there has been a great atmosphere as they have all helped each other.
"We have also got three good young keepers in the academy working with Vince O'Keefe."
Tunks is aware that it is a big year for both Friedel and Kelly as they look ahead to the World Cup and representing the States and Ireland respectively. Kelly is expected to return to light training next week although Tunks will be guided by the medical staff.
"I don't think many other clubs will have two keepers at the World Cup," he said and Friedel and Kelly will be certain to do themselves, their club and their countries proud.
Comments: Our rules
We want our comments to be a lively and valuable part of our community - a place where readers can debate and engage with the most important local issues. The ability to comment on our stories is a privilege, not a right, however, and that privilege may be withdrawn if it is abused or misused.
Please report any comments that break our rules.
Read the rules hereComments are closed on this article