GREATER NOIDA, India, March 16, 2013 (AFP) - Aiken, who began the day four shots behind the leaders, carded a flawless 62 to end the day at 18-under par 198, three strokes ahead of nearest challenger Liang Wenchong of China.
One shot behind the Chinese were Kiradech Aphibarnrat of Thailand and David Drysdale of Scotland at 202, setting up an intriguing finale on Sunday at the Greg Norman-designed par-72 Jaypee Greens outside New Delhi.
At least 12 more players were within seven shots off Aiken, throwing open the final round on a course that has seen scores of birdies and eagles over the first three days.
Aiken, looking for his second European Tour title after winning the Open de Espana in 2011, did not look back after putting a birdie on the first hole and hitting an eagle on the par-five second.
The 29-year-old from Johannesburg said the early success made him determined to stay consistent.
"I just concentrated on playing one shot at a time," he said. "I did not get ahead of myself at all. I just stuck to my gameplan. I relied on hitting some good iron shots and it worked today.
"I may have a three-shot lead but that does not guarantee me victory on Sunday. There have been so many low scores this week. All I can do is go about my business as I did today and hope for the best."
If Aiken wins on Sunday, it will mark the second victory by a South African of the Avantha Masters, following compatriot Jbe Kruger's success last year.
Liang was handicapped by two bogeys on the front nine as he came in at three-under 69, while Aphibarnrat and Drysdale slipped after dropping shots towards the end of their rounds.
India's richest golf event, now into its fourth year, is co-sanctioned by the European and Asian Tours.
Leading scores after the third round in the $2.3 million Avantha Masters golf at the Jaypee Greens in Greater Noida on Saturday:
198 - Thomas Aiken (RSA) 67-69-62
201 - Liang Wenchong (CHN) 66-66-69
202 - Kiradech Aphibarnrat (THA) 68-68-66, David Drysdale (SCO) 67-67-68.
203 - Scott Hend (AUS) 67-68-68, Joonas Granberg (FIN) 67-67-69, Tommy Fleetwood (ENG) 69-65-69.
204 - Gaganjeet Bhullar (IND) 68-69-67, Jaakko Makitalo (FIN) 67-68-69, Julien Quesne (FRA) 69-66-69, Chapchai Nirat (THA) 66-66-72
205 - Prom Meesawat (THA) 68-73-64, Boonchu Ruangkit (THA) 70-70-65, David Howell (ENG) 68-72-65, Kristoffer Broberg (SWE) 69-71-65, Rikard Karlberg (SWE) 67-69-69.
206 - Kim Gi-whan (KOR) 71-70-65, David Horsey (ENG) 72-68-66, Magnus Carlsson (SWE) 66-73-67, Jeev Milkha Singh (IND) 69-68-69, Baek Seuk-Hyun (KOR) 68-68-70, Maximilian Kieffer (GER) 68-68-70,
207 - Berry Henson (USA) 69-71-67, Lee Slattery (ENG) 72-67-68, Anirban Lahiri (IND) 68-69-70, Paul Waring (ENG) 70-68-69, Victor Dubuisson (FRA) 69-68-70, Pablo Larrazabal (ESP) 68-68-71, Adilson Da Silva (BRA) 70-65-72, Rahil Gangjee (IND) 69-66-72, Chinnarat Phadungsil (THA) 61-74-72
208 - Jyoti Randhawa (IND) 70-70-68, Siddikur Rehman (BAN) 73-67-68, Matthew Baldwin (ENG) 69-70-69, Andy Sullivan (ENG) 71-68-69, Peter Whiteford (SCO) 68-69-71.