Bangkok: Yuki Bhambri and his partner Ryler Deheart advanced to doubles quarter-final of the ATP Challenger event after their second seed rivals Evgeny Kirillov and Alexandre Kudryavtsev retired mid-way.
The unseeded Indo-American pair was leading 6-2, 6-6 when the Russian players opted out of the first round contest.
The lower back injury to Kudryavtsev forced the Russians to retire.
Yuki and Ryler will next take on Taipei pair of Chu-Huan Yi and Tsung-Hua Yang.
The Indian teenager, a Youth Olympics silver medallist, had crashed out of the singles event after suffering a 5-7, 1-6 defeat against fellow Russian wild card Dmitry Tursunov in the first round.