Birmingham: Buttler's international best performance effectively accounted for the victory margin with the Somerset batsman hitting three sixes and two fours.
The 22-year-old's deft use of the ramp shot and some powerful hitting was mainly responsible for South Africa left-arm quick Wayne Parnell conceding 32 runs in the ninth over -- the second most expensive in Twenty20 internationals.
Broad, who holds the unwanted record after being smashed for six sixes by India's Yuvraj Singh in an over costing 36 runs in 2007, was glad to see Buttler at last replicate his county form for England.
"We knew we had hitters to come in and Jos played a game-changing innings," said Broad.
"We've seen this fellow do it for Somerset time and time again, so to see him do it in an England shirt was brilliant," the seam bowler added.
"We look for guys who can change the momentum of games and Jos really did win us the game.
"Going into the final three overs it looked like we needed a push and Jos got 32 in 10 balls. That would change most games."
South Africa captain AB de Villiers, who as a wicket-keeper had a good view, paid tribute to man-of-the-match Buttler by saying: "You have to give credit where it's due and he certainly took it to us.
"I thought he hit a few very inventive shots and that's what's needed in this format."