Thomas, who is based in Dubai but carries an Indian passport and played in the recent Asian Games, turns 19 in five weeks. He is now Tied-8th at 7-under 203 and is just three shots behind the leader Lin Yuxin, the defending champion from China.
Lin Yuxin, who turns 18 in a week, played with Thomas and shot the week's best of 8-under 62 to take sole lead at 10-under 200.
Filipino Lloyd Jefferson Go (69) hung in well to card a gritty 1-under 69 after dropping a double on eighth and another bogey on 15th. He is 9-under, one behind the lead and second.
Five players, including the 2016 champion, Cheng Jin (70), 2018 Asian Games double gold medallist Keita Nakajima (67), Japan's Asian Games team gold medallist Takumi Kanaya (64), highly-rated Thai KK Limbhaust (68) and China's Zheng Kai Bai (69) are Tied-3rd.
On a day when overnight co-leaders Jefferson Go and Cheng Jin were subdued with 69 and 70, a bunch of others made a sharp move up. They included leader Lin Yuxin (62), Indonesian Naraajie Ramadhan (63), Kanaya (64) and last year's runner-up Andy Zhang (64). The last three are T-8th with India's Thomas (65).
Left-hander AAC debutant Kartik Sharma recovered well from a double bogey and a bogey between 11th and 13th to shoot 1-under 69 and at 4-under 206 is Tied-14th.
Yuvraj Sandhu of Chandigarh moved up to T-20 with even par 70 and at 2-under 208, while Kshitiji Naveed Kaul (71) was Tied-47th and Varun Parikh (71) T-51st.
Thomas got off to a shaky start as he realised he had forgotten his yardage book back in the hotel and the battery in his Range finder ran out on the first hole itself.
"Despite that I managed a birdie on second. I borrowed a battery and got a new yardage book, but was still without my first two days of notes," said Thomas.
"But happily I hit it great and putted well, though a couple of more could have gone in. Still bogey free is a good feeling and being three behind is great after being 10 back at the end of the first day and six after second," added Thomas, who is bogey over last 27 holes and has just one in last 37.
Lin Yuxin before the event had said he would do everything in his power to keep the Trophy for another year and kept that promise. Injured till a few weeks ago, he admitted he was not hitting it well before coming here.
(This story has not been edited by Social News XYZ staff and is auto-generated from a syndicated feed.)
