Allen, who had trailed Zhang Anda 5-2, transformed the match in a blistering spell, reeling off six consecutive frames to seal a 10-6 victory.
A scrappy contest turned on two moments of clarity: breaks of 140 and 109 either side of the interval ignited the comeback, after which Zhang barely scored.
From there, Allen, suddenly fluent, closed with further contributions of 129 and 81 to complete an emphatic turnaround.
On the adjacent table, Ding underlined his status as a contender with a clinical display against David Gilbert. Breaks of 94 and 74 helped him into a 3-1 lead, and although Gilbert briefly resisted, Ding’s scoring and control proved overwhelming.
A century and further runs of 72 and 52 carried him to a dominant 7-2 advantage, his superior potting and long game leaving Gilbert with little margin for error.
Higgins collapse
Elsewhere, Higgins produced one of the most uncharacteristic sessions of his career. The four-time champion raced into a 4-0 lead against Ali Carter, only to lose his way completely.
A missed red to go 5-1 ahead proved pivotal; from that moment, Higgins contributed almost nothing, while Carter, still far from his best, capitalised to win five frames in a row and lead 5-4.
Barry Hawkins, by contrast, ensured there would be no such drama. Already in control against Matthew Stevens, he absorbed a brief rally before closing out a comfortable 10-4 win with breaks including 92 and 70, booking his place in the second round with minimal fuss.