The opening race was a virtual dead heat between Anna Jesien (POL) and Huang Xiaoxiao (CHN). The Pole overtook the Chinese hurdler at the last moment as both were given identical 54.34 times. For the extremely elated Huang, it was a personal best and only her second lifetime performance under 55 seconds. She had held the lead for most of the second half of the race, losing it only in the last metre.
Andrea Blackett (BAR), running in an outside lane, sprinted hard on the run-in to take third in a season-best 54.79, as one of the early leaders, Athens bronze winner Tetiana Tereschuk-Antipova (UKR), faded in the final metres to finish fourth with 55.13. Both Blackett and Tereschuk-Antipova ultimately advanced to the final based on their times.
Shauna Smith (USA), pinned to the curb in lane one, never could get into the race, and despite her relatively high position on the year list she finished seventh in 55.97.
Paris silver medallist Sandra Glover (USA), competing in the second heat, ran a even race and was rewarded with a lopsided 54.16 win, as Malgorzata Pskit (POL) took the important second-place (and auto-qualifying) spot with a distant 55.20.
Tawa Dortch (CAN), from her position on the outside, had led the race up through the eighth barrier, but she ran out of energy and finished fourth in 55.58, still a PB, being pipped just before the finish by Benedetta Ceccarelli (ITA) in 55.41.
World-leader and world-record holder, Yuliya Pechonkina (RUS), stutter-stepped the first hurdle, giving an ephemeral lead to Marta Chrust-Rozej (POL) running on the outside of the Russian. However, by the third barrier, Pechonkina was back in synch and sailed to a 53.86 win, the fastest of the day.
Lashinda Demus dispensed with her usual hell-bent tactics, going instead for a certain qualifying spot by easily finishing second in 55.00, ahead of Surita Febbraio (RSA) with 55.74 and Debbie-Ann Parris-Thymes (JAM) at 55.96. Chrust-Rozej, after her momentary lead, faded to sixth in 56.80.
