Ping!
The Austrian General Staff planned a brilliant offensive right through the Serbian Army's Artillery Training Area, in which every tree, rock, gully and goat was well registered and co-ordinated, not to mention the Serbians' Slavic Big Brothers, the Russkis, pretty much had bought the Austrian plans!
Still, the Serbs were utterly worn out from throwing the Turks out of the Balkans (with the help of Surprise >>>The Italians?) and it's true that "rag-tag" is an accurate description of their resources. However, they had a very experienced general staff a good officer corps, honest-to-god fighters, and very good artillery, some of it captured Krupp stuff from the Turks. They quite literally wiped the floor with the Austrians in Round 1, who, beaten soundly on the field of battle, committed the most bizarre and senseless atrocities upon helpless civilians on retreat from this campaign.
One would think the Austrians might have gone back to Vienna after this Balkan version of Custer's Last Stand ... but no, they brought in the Germans. That's because, not only were the poorly equipped Serbians cleaning their clock, but the Russkis were really kicking their ass down the street on the Eastern Front.
Who started WWI? The Austrians who dragged in the Kaiser when they were beaten fair and square on two fronts. The Kaiser for being stupid enough to help'em out when it wasn't necessary, and most of all that dumkopf Czar Nick who was just feeble-minded enough to invade Germany and parts of the Eastern Austro-Hungarian Empire, when it wasn't at all necessary, seeing as how his Cousin Kaiser Bill wasn't even mad at him, (largely because KB knew the his Cousin Nick was an idiot and henpecked besides.)
BTW, don't all you Serbians sic your hounds on me when I report that my Grandfather who served as a liaison officer to the Montenegrin General Staff, used to tell us war stories,in which the ..."Montenegrins were Bravest of all ... and their women ...spectacular."