Langer's double-bogey blunder at the last regulation hole on Sunday - when he only needed a one-over-par five for victory - gave Wiebe an unlikely opening and, after bad light forced the pair to return to the Merseyside course for a fifth day of competition, the 55-year-old eventually came through at the fifth time of asking to secure the biggest win of his career.
Sky Sports expert Riley applauded the performance of Wiebe, who had never made the cut at The Open in his career, and said the popular player will take huge confidence from his display on the testing terrain of Royal Birkdale.
"This is really good for him," Riley told Sky Sports.
"He's had a tough time, he hasn't had a top ten for a while on the Champions Tour and he's had a lot of ailments and back problems. So to come here and win the Senior Open Championship at a place like Royal Birkdale is top notch stuff.
"He's a great player and exemptions come with this for him on the Champions Tour. He's not one of those guys who has had big championship wins so this is really good for him."
The unfancied American finished clear of far more decorated opponents such as Corey Pavin and Sandy before outlasting Langer - who won this event three years ago - and Riley reckons the strength of the field, combined with the history of Royal Birkdale, will add to the satisfaction for Wiebe.
"He's beaten legends, great players," said Riley. "And when you win at a special place it really does help as well.
"'Where did you win the Senior Open, Mark Wiebe?' 'I won it at Royal Birkdale.' That's got a nice tune to it...
"He's a quiet, big guy and he's a good laugh, and a confident player. He's not got the prettiest golf swing in the world but he gets the job done and now he can have a nice trip home.
"He'll be sitting on the plane thinking 'I've just won that, look what I've got in my pocket. Brilliant'."
However, in contrast Langer will be left to reflect on his slip-up at the 18th on Sunday which effectively cost him the tournament.
"Bernard Langer is a great champion but last night, over in the right hand bunker on 18 he took two to get out of it and made a double bogey.
"He's now lost it this morning and he won't feel the best."
Watch the World Golf Championship-Bridgestone Invitational from 7pm, Thursday on Sky Sports 3 HD