Johns and Boulton have endured a difficult season but they showed their undoubted ability in a straight sets but closely fought 21-19 21-19 victory, secured in 39 minutes. It was their third career match against the Chinese and their first win - and what better place to do it than the London 2012 test event on the iconic Horse Guards Parade
"It just keeps getting better," said Boulton, who will now face American world number four pair Jennifer Kessy and April Ross in the semi-finals. "The crowd was amazing and it was great to showcase our sport in front of so many people from Great Britain. "At the end of the first set, we stayed with them and then traded, traded, traded. They could have taken it but we took them. They are a great team and I am sure they will return to London next year for the Olympics."
However, there was disappointment for British top seeds Zara Dampney and Shauna Mullin, who were beaten 21-14, 22-20 by Brazil's Liliane Maestrini and Angela Vieira, who now face team-mates Vivian Cunha and Taiana Lima in the other semi-final.
Britain has been guaranteed one host nation place at next year's Olympics and unless one of the pairings can edge into the top 23 of the world rankings by next June, it is looking a tough call for selectors.
"At the moment Zara and I aren't too far off qualifying in our own right in the top 16," said Mullins. "It's key to get some good results in the Opens at the end of the year. If we were able to do that, that would free up the wildcard spot."