Wilfried Bungei of Kenya was in control of the first semifinal for most of the way, with American David Krummenacker moving into contention near the halfway mark.
Holland’s Bram Som waited until about 600 metres remained to approach the lead pair, and Botwanan Glody Dube followed suit.
Off the final bend, Bungei (1:47.04) strode confidently into the finish ahead of Krummenacker (1:47.30), while Som’s (1:47.57) determined sprint over the last fifty metres fended off a last-second effort of the non-advancing Dube (1:47.63).
Spain’s Antonio Reina set the pace for the second semifinal, but Wilson Kipketer of Denmark took over after two laps. The World Record holder ran unchallenged the rest of the way to a winning 1:47.84.
Meanwhile, the second Dutch runner, Arnoud Okken, appeared to try and challenge Kipketer and Reina in the final lap. The increase in tempo brought Okken (1:48.26) past Reina (1:48.27) in the final turn, although the Spaniard did came back strongly in the final steps, just missing out on second as the Hollander prevailed, 1:48.26 to 1:48.27.
Commonwealth silver medallist Joseph Mutua of Kenya looked surprisingly ineffective off the final turn, as his 1:48.46 was not sufficient for advancement to Sunday’s final.