Prakash Amritraj entered the quarter-finals of the 416,000 Campbell's Hall of Fame Tennis championships at Newport, Rhode Island, in the United States, beating American wildcard Scoville Jenkins 6-4, 6-3.
The US-based Indian Davis Cupper, who beat Serbian Ilia Bozoljac 3-6, 6-3 6-3 in the first round of the grass court tournament, maintained his good form going to enter the last eight stage for the first time.
Prakash, who is ranked 467th in the world and had to qualify for the tournament, next faces fifth-seeded Frenchman Nicolas Mahut for a place in the semi-finals.
The 83rd ranked Mahut, who beat world number two Rafael Nadal in the semi-final at Queen's club last month before losing to American Andy Roddick in the title match, beat compatriot Antony Dupuis 6-3, 6-7(5), 6-1 to move into the quarter-finals.
Pakistan's Aisam-ul-Haq Qureshi, who upset top seeded American Mardy Fish in straight sets in the opening round, also moved into the last eight.
The 214th-ranked Qureshi defeated Australian Nathan Healey 7-6(2), 5-7, 6-4 and next faces unseeded Belgian Dick Norman.
Norman beat eighth seed Michael Berrer of Germany 6-2, 6-7(4), 7-6(6).
If Prakash and Qureshi win their respective quarter-finals, they will face each other for a place in the final.
Prakash and Qureshi, however, lost to top seeds Moodie and Santoro 6-0, 6-4 in the first round of the doubles.