Complex sentence: The advice proved sound, as the Turgesh caught up with them and would likely have annihilated Junayd's army on open ground, but as it as, the camp's fortifications could not be completed before the next day, when the Turgesh renewed their attack.
Split into simpler sentences: The advice proved sound, as the Turgesh caught up with them and would likely have annihilated Junayd's army on open ground. As it was, the camp's fortifications could not be completed before the next day, when the Turgesh renewed their attack.