Chingghis Khan’s greatest failure

By his own battle he only lost to Jamukha's soldiers, around current Onon river's /Northeast Mongolia/ starting mountains. This was however a pretty domestic rebel type of fight but he lost,

Later I heard, near Samarkand or something his one of good /but not good/ heroes called Shihihutug waiten quite big loss to Jelal Ad-Din's troops, and barely 30000 soldiers from Mongolia were dead, However all the middle east became attributed to Mongolia after hard effort of Ghengis Khan and his offsprings,