Rising for the third straight session, the Sensex at the Bombay Stock Exchange climbed 124 points, to 18,238 in opening trade Friday morning, amid firm Asian bourses.After paring its gains, the Sensex stood 34 points, or 0.2 percent in the green, at 18,147, a short while ago.Domestic investor sentiment was supported by gains in the bourses in Japan, Hong Kong, China, Indonesia, South Korea, Taiwan, and Singapore, which were up by between 0.1 percent and 2.2 percent, on Friday.Asian stocks rose on upbeat guidance from select US blue-chip companies, and a strong 2 percent rally in the US Dow Jones Industrial Average, overnight.