 Xiphias is next mentioned in the Battle of Kleidion in 1014, when Basil II was attempting to force the pass known as Kleidion or Kiava Longos, which the Bulgarians under their ruler Samuil had strongly fortified. Xiphias, still strategos of Philippopolis, suggested to the Emperor to bypass the Bulgarian positions and strike them from the rear. After Basil agreed, Xiphias led a picked infantry detachment over Mount Belasica, and on 29 July 1014, led his troops on a charge on the unsuspecting Bulgarians, who panicked and broke before the unexpected attack. For this feat, which resulted in one of the most decisive victories in the long Bulgarian war, he was rewarded with promotion to the rank of patrikios. In early 1015, Xiphias, along with Constantine Diogenes, subdued the region of Moglena, which had rebelled against imperial rule. Towards the end of the same year he campaigned from Mosynopolis to the region of Triaditza (Sofia), razing its environs and capturing the fort of Boyana. Finally, in the last year of the Bulgarian war, in 1018, starting from Kastoria he subdued the remaining Bulgarian strongholds in the region of Servia.
