The Cape Cobras off-spinner, who was given an opportunity at the expense of Simon Harmer, ended with 4/101 in 34 overs and made some serious inroads into the Indian batting line-up.
Bad light ended play with six overs left in the day at the Feroz Shah Kotla Stadium, with India ending on 231/7 in 84 overs.
Piedt, who has been out of the game for several months with a serious shoulder injury, was unlucky not to clinch his first Test five-wicket haul in just his second Test as captain Hashim Amla dropped Ajinkya Rahane late in the day.
The 25-year-old Capetonian got the ball rolling for the Proteas after India had made a sound start as he lured Murali Vijay (12) into hanging his bat outside off, and the edge carried to Amla at slip.
Piedt struck again after Shikhar Dhawan and Cheteshwar Pujara established a 32-run partnership when he dismissed Dhawan with a straight ball that trapped the left-hander LBW for 33.
Kyle Abbott, who came in for the rested Kagiso Rabada, bowled consistently well throughout the day, and he was rewarded for his accuracy when an in-swinger found the inside edge of Pujara's bat and crashed into the stumps.
On a pitch that had uneven pace and bounce – although it played significantly better than the Mohali and Nagpur tracks – Piedt and Abbott (3/23 in 17 overs) were the pick of the Proteas bowlers.
But the Indian middle-order showed some fight, with captain Virat Kohli leading the way with an entertaining innings of 44 (62 balls, 7x4). He played some glorious shots around the wicket, and looked set for a big score when Piedt managed to get rid of him in fortunate circumstances for the South Africans.
Kohli swept the ball powerfully to the leg-side, but the ball struck Temba Bavuma – who replaced Stiaan van Zyl in the starting XI – at short leg and looped up, and wicket-keeper Dane Vilas showed great agility to come out from behind the stumps to dive on to the pitch and take a superb catch.
That rocked the Indians as Kohli is a key figure, and Rohit Sharma (1) followed soon after when he skied Piedt to Imran Tahir at wide long-on after Sharma had been dropped by Amla at slip off Abbott in the previous over.
But Rahane wasn't going to give his wicket away as easily, and he kept his composure and took a particular liking to Tahir to race into the 70s.
However, with Rahane on 78, Piedt found the edge of his bat, but Amla put a relatively easy chance down.
How costly that missed opportunity will prove to be for the South Africans will be known on Friday, as Rahane swiftly moved on to 89 not out off just 155 balls (9x2, 2x6).
He received good support from Ravindra Jadeja (24) down the order, and Ravichandran Ashwin (6 not out) has scored Test hundreds before and could be difficult to dislodge on day two on a decent batting pitch.
Morné Morkel (0/40 in 17 overs) bowled well without reward, but Amla will be concerned about Tahir's performance as the leg-spinner conceded 36 runs in seven overs.
India have won the Test series 2-0 already, but the Proteas are hoping to end the tour on a high after success in the ODIs and T20s.
@IndyCapeSportDane Piedt made a strong return to Test cricket on Thursday as the Proteas edged ahead on day one of the fourth and final Test against India in Delhi.
Original source: Piedt, Abbott star for Proteas