Anastasija Cvetkovic will advance against Siyun Xiao at the W35 Kursumlijska Banja in Serbia on September 2, sending her deeper into the $30,000 outdoor clay event that runs August 31 to September 6. Cvetkovic will carry momentum from her recent W35 Verbier title where she beat Anđela Okutodži 6:4,…