While Berdych missed out on crucial points in the race to be in London next month, third seed Rafael Nadal moved closer to confirming his place as he booked a quarter-final spot.
Berdych had won his first tour of the year in Shenzhen, but threw in 32 unforced errors in losing in one hour and 46 minutes.
“It’s always a hard part of the year”, he said.
The 14-time Grand Slam victor had his service broken four times in the first round by China’s 230th-ranked Wu Di, but he showed better signs against Pospisil, the world number 44.
Against Pospisil, Nadal only faced one break point – and he saved it.
Berdych said the short turn-around after Monday’s final in Shenzhen made it hard to adjust to the conditions in Beijing.
Next up for the 33 year old is Chinese Taipei’s Yen-Hsun Lu, who continued to make the most of his wild card to upset Milos Raonic’s conqueror Viktor Troicki 6-4, 7-5.
However, 13th seed Andrea Petkovic’s China Open is over after she was bundled out in three sets by Italy’s Sara Errani, 3-6, 6-3, 6-2.
Later, Wozniacki was brutally disposed of by a grimly determined Angelique Kerber 2-6, 3-6 as the Dane’s hopes of reaching the year-ending WTA Finals took a hit.
“I think I want to finish in a good way the year”. That was my assessment after Wuhan.
Air pollution which had hovered at hazardous levels magically lifted by the end of eighth-ranked Nadal’s match, and his spirits would have risen too as he aims to fight his way back to the top.
Switzerland’s Bacsinszky edged a topsy-turvy match, which had 11 breaks in total, with seventh-seed Carla Suarez-Navarro of Spain, winning 6-4 4-6 7-5 to progress.
Fourth seed Agnieszka Radwanska set up a quarter-final with Kerber after Madison Keys retired after their first set, becoming the sixth player to withdraw mid-match.
With Serena Williams and Maria Sharapova both missing Beijing, the women’s draw has been prised wider open by the retirements of Simona Halep and Eugenie Bouchard, and Petra Kvitova’s early defeat.