
The duo, who gained entry as lucky losers because of an injury default to Jan-Michael Gambill, stunned top seeds Bobby Reynolds and Rajeev Ram 6-3,6-4 in the opening round.
Amritraj, 23, and Davidson eventually lost 5-7,2-6 to fourth seeds Robert Kendrick(US) and Cecil Mamiit(PHI) in the semifinal.
Stephen, son of former tennis player Anand Amritraj, had partnered cousin Prakash to reach the semifinals of the Fergana Challenger earlier this year.
Back home in India, newly crowned National hard court champion Ashutosh Singh spearheaded the country's challenge at the India F9 Futures in Bellary, Karnataka.

Singh, ranked 659 on the ATP list, lost to third seeded Austrian Rainer Eitzinger 4-6,3-6.
But he gained revenge by partnering Vivek Shokeen (in pic) to beat Eitzinger and Philipp Oswald 7-6(4),3-6,10-5 in the doubles final.
Wildcard Rupesh Roy, who lost in the quarterfinals to Singh, also impressed with a second round win over Romania's Adrian Gavrila.
Elsewhere in Europe, Sania Mirza lost in her Zurich Open opener before retiring for the season while Leander Paes and Martin Damm lost in the second round of the Madrid Masters doubles.
Sunitha Rao, who reached the finals at the ITF San Francisco Tennis Classic last week, withdrew from the ITF Lawrenceville Challenger at the last minute.

Partnering Nungnudda Wannasuk of Thailand, Iyer also lost to Adamczak and Briton Jade Curtis 7-6(2),6-7(3),5-10 in the doubles quarterfinal.