Tendulkar top-scored with 55 as India made 200 for nine after being sent in to bat on Sunday.
He made his runs off 97 balls having scored only four off the first 40 deliveries he faced.
South Africa hold an unbeatable 3-0 lead in the series, with one match washed out.
Tendulkar made an unusually watchful start after seeing captain Virender Sehwag and VVS Laxman dismissed off successive deliveries from Shaun Pollock with the total on 18.
His first boundary came in the 16th over and it was the start of a more characteristic display from India's master batsman, who hit seven more boundaries before slapping a short ball from Justin Kemp to cover, where AB de Villiers took a diving catch.
Tendulkar and Dinesh Mongia (41) put on 85 off 149 balls for the third wicket but the only other significant innings came from Mahendra Singh Dhoni, who made an aggressive 44 off 49 balls before falling to a sensational diving catch by Andre Nel at long-on off Makhaya Ntini in the 48th over.
Ntini took three for 32, taking all his wickets in his final two overs, but Pollock was the most impressive bowler, taking two for 17 in his ten overs.
It completed a fine series for Pollock, who took ten wickets at an average of 8.30 in four matches.
It was the fourth successive time South African captain Graeme Smith won the toss but the first time he decided to send in the opposition.
South Africa made two changes from the team that won the fourth match in Port Elizabeth by 80 runs. AB de Villiers moved up to open the batting in place of Loots Bosman, while Ashwell Prince came in to the side to bat at number five. Left-arm spinner Robin Peterson replaced Andrew Hall.
India brought in the experienced Laxman, who flew to South Africa as a replacement for injured captain Rahul Dravid, as one of three changes. Also in were Mongia and Harbhajan Singh, while Wassim Jaffer, Mohammed Kaif and the injured Ajit Agarkar were left out. Agarkar suffered a groin injury during India's win in a Twenty20 international in Johannesburg Friday.