The Chinese pair have recovered well since losing their opening game of the tournament last weekend and looked somewhere close to their best this evening as they outclassed Austrian sisters Doris and Stefanie Schwaiger 21-18 21-11.
Austria, making their second successive appearance in the last eight at the Olympics, matched Zhang and Xue for much of the opening set but China's narrow win gave way to a one-sided second set as the Asians dominated the net.
For the Schwaiger sisters the loss mirrored their Beijing 2008 exit, which also came about as a result of going up against a Chinese pair, Tian Jia and Wang Jie, who went on to claim the silver medal.
Silver would represent an improvement for Zhang and Xi, who took bronze four years ago, but both will feel a gold medal is well in their sights after another strong showing tonight.
'It was a tough match,' said Zhang. 'We never scored so much that we were that far ahead and, if we did get a good lead, the Austrians managed to catch up.'
Asked about her hopes for the rest of the tournament, she added: 'My goal, the one I set at the start, is for us to reach the final.'