On 13 July 1913, General Mihail Savov assumed control of the 4th and 5th Bulgarian armies.^[74] The Bulgarians then entrenched themselves into strong defensive-positions around the village of Kalimanci, near the Bregalnica River in the northeastern part of Macedonia.^[74]

On 18 July, the Serbian 3rd Army attacked, closing in on the Bulgarian positions.^[74] The Serbs threw hand grenades at their enemies in an attempt to dislodge the Bulgarians, who were sheltered 40 feet away.^[74] The Bulgarians held firm, and on several occasions they allowed the Serbs to advance. When the Serbs were within 200 yards of their trenches, they charged with fixed bayonets and threw them back.^[74] The Bulgarian artillery was also very successful in breaking up the Serb attacks.^[74] The Bulgarian lines held, an invasion of their homeland was repelled, and their morale grew substantially.^[74]

If the Serbs had broken through the Bulgarian defences, they might have doomed the 2nd Bulgarian Army and driven the Bulgarians entirely out of Macedonia.^[74] This defensive victory, along with the successes of the 1st and 3rd armies in the north, protected western Bulgaria from a Serbian invasion.^[75] Although this victory boosted the Bulgarians, the situation was critical in the south, with the Greek Army defeating the Bulgarians in numerous skirmishes.^[75]