Runs of 34 and 86 in frame six opened up a 4-2 advantage for the Australian as he looked set to secure his spot in the next round.
"I was really happy to make that break in the last frame," said Robertson, who has been suffering from a viral infection.
"I am not 100 per cent healthy yet, but I'm still here. After my previous match I had no energy and I was just fortunate that I had a day off to recover.
"I just need to try and rest again and prepare as well as I can for my next match. I have shown my fighting qualities and that's what has got me through the first two rounds."
Robertson’s opponent in the last-16 will be China's Yu Delu, who beat James Wattana 5-1.
Former China Open champion Peter Ebdon beat Judd Trump 5-4 to join Robertson in the last-16.
In a tightly fought affair, fourth-seeded Trump had led 4-3 following runs of 33 and 23 in frame seven but 'The Ebdonator' took frame eight courtesy of breaks of 48 and 30 before a superb break of 86 in the decider sealed his progression.
"We both missed a few balls so perhaps the standard could have been a bit higher but I was very pleased with today's result," said Ebdon.
"I always looking forward to coming back to Beijing because I knew the conditions will suit me. It's important to be coming into form at this time of the year.”
Round two results
Craig Steadman 5-4 Martin O'Donnell
Jamie O'Neill 5-2 Fergal O'Brien
Mark King 5-3 Marco Fu
Ding Junhui 5-3 Thepchaiya Un-Nooh
Mark Selby 5-1 Nigel Bond
Neil Robertson 5-4 Mark J Williams
Graeme Dott 5-4 Dave Harold
Allister Carter 5-2 Matthew Selt
John Higgins 5-1 Michael White
Shaun Murphy 5-0 Dechawat Poomjaeng
Peter Ebdon 5-4 Judd Trump
Luca Brecel 5-1 Dominic Dale
Jimmy White 5-3 Alfie Burden
Ricky Walden 5-3 Xiao Guodong
Mike Dunn 5-3 Tian Pengfei
Yu Delu 5-1 James Wattana
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- Judd Trump