South Africa, who played a disciplined game, scored through Lyle Foster(21st minute), Mswati Mavuso (54th) and Luke le Roux (82nd).
Russia, who enjoyed territorial advantage, created several chances but could not get past rival custodian Glen Baadjie. However, Russia pulled one back through Skrobotov IIia in the 45th minute.
South Africa, who finished second with seven points from four matches, will face Brazil in the final on Saturday.
Russia, meanwhile, finished third with six points from as many matches.
Russia, who needed a draw to make it to the final, started well and created couple of scoring chances but could not get past rival keeper Glen, who stood tall in front of the goal post.
Russia, who went into offensive in search of the equaliser, came close with Kolesnichenko Kirill and Lopatin combining well upfront.
However, Russia drew level in the dying minute of the first half from a corner with Skrobotov IIia deflecting the ball into the net as Glen was beaten by the flight of the ball.
Unpreturbed by the set back, Russia kept on mounting pressure on their rival and had two clear chances but first Klesnicheako Kirill's left footer was put out by keeper Baadjie and few minutes latter Kirill and Daniil failed to put the ball into the net off a cross from the right after the South Africa defence was beaten.
South Africa came up with a counter move and sealed the victory with another goal in the 82nd minute.
A long lob on top of the box saw Russian defender Ianov Danila's feeble clearance go to Luke Le Roux, who uncorked a pile driver that found the far corner of the net.
(This story has not been edited by Business Standard staff and is auto-generated from a syndicated feed.)