Team USA's Sam Watson climbed up the wall in 4.75 seconds, 0.04 seconds faster than the world record previously set by him in April.
Indonesian Veddriq Leonardo came second with 4.79 seconds, followed by Kazakhstan’s Amir Maimuratov (4.89).
Alipour qualified for the final with a run time of 5.06 seconds as the fastest elimination heat loser.
The top eight men advance to the final on Aug. 8.
Men's speed semifinal (Top 8):
Sam Watson (USA): 4.75 seconds (WR)
Veddriq Leonardo (INA): 4.79 seconds
Amir Maimuratov (KAZ): 4.89 seconds
Matteo Zurloni (ITA): 4.94 seconds
Wu Peng (CHN): 5.00 seconds
Bassa Mawem: 5.16 seconds
Julian David (NZL): 5.20 seconds
Reza Alipour (IRI): 5.06 seconds
AMK/TT