This event prompted Maslama to take over personally the direction of the Khazar front in 727, where now he was faced, for the first time, by the "khagan" himself, as both sides escalated the conflict. Maslama, probably reinforced with more Syrian and Jaziran troops, took the offensive. He recovered the Darial Pass, apparently lost in the period since al-Jarrah's expedition in 724, and pushed on into Khazar territory, campaigning there until the onset of winter forced him to return to Adharbayjan. Whatever Maslama's achievements in this expedition, they were not enough. The next year, when he repeated his invasion, it ended in what Blankinship calls a "near disaster". Arab sources report that the Umayyad troops fought for thirty or even forty days in the mud, under continuous rainfall, before scoring a victory against the "khagan" on 17 September 728. How great that victory was, however, is open to question, because on his return Maslama was ambushed by the Khazars, whereupon the Arabs simply abandoned their baggage train and fled headlong through the Darial Pass to safety. In the aftermath of this campaign, Maslama was replaced yet again by al-Jarrah al-Hakami. For all his energy, Maslama's campaigning failed to produce the desired results: by 729, the Arabs had lost control of northeastern Transcaucasia and been thrust once more on the defensive, with al-Jarrah again having to defend Adharbayjan against a Khazar invasion.