Stung by the criticism from his naval superiors in Pola, who focused on the apparent lack of energy which permitted the Serbian guns to advance so far towards Novi Sad, Ritter von Trapp immediately dispatched forces to fortify the Danube against "excursions" such as that made by the Serbians. In the eyes of the country, even though most eyes were still focused on Poland and the depredations of the Tsar's hordes, the action at Belegis was an embarrassment. That Serbia, which not dissolved itself out of shame, could have advanced into South Hungary so far and so quickly without the knowledge of the forces on hand was unthinkable. Ritter von Trapp fired off a strongly worded statement to the effect that such could not happen again. He reiterated his policy of waiting for the first aggressive action to be Serbian, now met by the advance of the Serbian shore batteries, but promised prompt and forceful action. Indeed one particularly flowery section indicated that no Serbian gunboat would catch the flotilla by surprise while the sun shone. Wags, of course, wondered if the Serbians would try to navigate the shallows by night

The Serbians had carefully inched up the Danube to take another shot at the Austro-Hungarian defenses with an eye towards throwing a few shells into Novi Sad for the sheer audacity of it. Serbian commanders accurately believed that the heavy lifting would be done by the Russian Army and that their activity was merely a sideshow. In order to have a place at the table when peace would be made it was essential for them to be active, and the sooner the better. Meanwhile, Ritter von Trapp was not caught by surprise by the Serbian foray. Spending most of the 29th sighting and fortifying his guns he got back to Novi Sad just in time to hear the reports from river watchers that several Serbian gunboats were under way. Having patched up the few holes that they had received on the 28th, the Kupa and Vltava set off back downstream, this time to defend the island at Belegis. As the sun's first rays shone from the east, the first ship to ship gunfire echoed across the Danube.