It was as the governor of Bashan Commandery that Xiao served under the major general Wu Mingche in 573 as Wu, commissioned by Emperor Wen's brother Emperor Xuan, led a campaign against Northern Qi, seeking to capture the region between the Yangtze River and the Huai River.
In spring 589, when Xiao was at Jiankang, the Sui general Heruo Bi (賀若弼) took the chance to cross the Yangtze (as part of the overall campaign by Emperor Wen of Sui to destroy Chen) and captured Jingkou (京口, the capital of Southern Xu Province).