An Qingxu
In fall 758, Tang forces closed in on Yecheng. An Qingxu had himself, Tian, and Cui Qianyou () command the Yan army to fight against the converging Tang forces, but Tang forces defeated them, forcing them to withdraw within the city to defend against the siege. It was only in 759, when Shi Siming fought an inconclusive battle near Yecheng that forced Tang forces to withdraw, that the siege on Yecheng was lifted. Shi then killed An Qingxu and took over the Yan throne himself, and Tian continued to serve under Shi. Shi soon advanced south with Tian as a forward commander and recaptured Luoyang. In winter 760, as part of a campaign to capture Tang territory, Shi sent Tian to the Huaixi region (淮西, i.e., modern southern Henan), but little is known about how successful the campaign was.