Sinclair scored 82.53 points in her second run with a Frontside 720 Melon Grab, Cab 360, Frontside 540, Backside 540, Stalefish and Method Air.
26 women competed for five spots that will advance to Friday's semifinals. Japanese riders Haruna Matsumoto and Hikaru Oe placed first and third respectively. Matsumoto's second run earned her first place with a scoring run of 83.65 and included a Frontside Air, Method Air, Frontside 540, Backside 540 and Frontside 720. Rounding out the top five were Xuetong Cai (CHN) and Holly Crawford (AUS).
Men's pre-qualifiers were split into two exciting heats where the top 25 men advanced to the qualifiers later in the day. Kazuumi Fujita (JPN) and Brett Esser (USA) stayed strong throughout pre-qualifiers and qualifiers as they were both top five in their first heats and continued on to the top two seats in the qualifiers.
Esser dominated the day coming out in first place overall with a strong second run that scored 81.58 points. Starting with a Frontside 1080 Tail Grab, he then moved into a Cab 720 Lien, Frontside 900 Tail Grab and Backside 900. Fujita was not far behind in second place with a second run that scored him 80.98 points. He earned the high score with a Crippler, Backside 540, Frontside 720, Cab 720 and Frontside 900.
In third place was another strong Japanese rider, Ikkou Anai, who scored 80.70 points in his last run of the day. Others that made the cut today were Tore Holvik (NOR), Sato Shuhei (JPN) and Dylan Bidez (USA).
New Zealand's James Hamilton placed 11th in a field of 29 in the prequalifiers which progressed him through to the qualifiers where he placed 17th, failing to make the top ten and through to the semifinals.
Those that made the cut will compete against halfpipe greats and invited riders, Danny Davis (USA), Queralt Castellet (ESP), Hannah Teter (USA), Iouri Podladtchikov (SUI) and Kelly Clark (USA) in the semifinals on Friday and Saturday.
The 2011 BNZO marks the first stop on the prestigious Burton Global Open Series and is also a 5Star event on the Swatch TTR World Snowboard Tour.