It seems the general strategy against mongols is to get out of their way and then defeat them in a slow battle of attrition. They will eventually spread their forces out across northern turkey and russia and you can pick them off in a number of large battles, using those armoured arabic spearmen and some lancers to deal with their horse archers.

Either that or you can spend 30 years preparing for one great super battle when they come marching into khazar and training up a lvl 8 general.