First Battle

Jeremi Wiśniowiecki, expecting an attack by the Krzywonos (about 60,000 men, including 20,000 seasoned veterans and 40,000 Tatars), captured Konstantynów and set up camp along the Słucha River. The Polish army advanced along the Sluch River. A scouting party reported the approach of the enemy. Soon a powerful Cossack army appeared on the right bank of the Sluch. The Polish army was positioned in its traditional way: Krzysztof Korycki and Janusz Tyszkiewicz's cavalry were on the right wing, Wiśniowiecki and his cavalry were on the left, and the infantry and artillery were in the centre. The enemy was on the other side of the river, allowing the Polish scouts to cross. After a brief melee, the Polish scouts withdrew. Krzywonos, confident of his numerical superiority, launched a frontal attack. Ivan Hira and a cavalry regiment from Bialystok attacked the Poles in front and drove them back across the river. The crossing was defended by Obersteiner Samuel Osinski with a company of musketeers and several regimental guns, supported by a battery of several cannons from Wiśniowiecki. The fire was so intense that the Cossacks retreated in confusion. Now several cavalry flags struck the Cossacks and pursued the fleeing men to the Cossack camp, a mile and a half away. The cavalry then overran the surrounding hills, awaiting the arrival of the infantry and artillery needed to storm the camp. In view of the falling dusk and the considerable numerical superiority of the Cossack army, the capture of the stockade was abandoned and the cavalry was withdrawn back to the Polish bank of the river. On that day, the Cossack army lost 2-3 thousand men, not counting prisoners of war (including Polujan).

Second Battle

After the Polish stock and infantry had departed at a distance of two miles from Konstantinovsk, the Cossacks moved to attack. The ford was initially defended by an infantry company (120 soldiers) under Osinski, but it was soon withdrawn and was defended by Dominik Zaslavski's dragoons during the main attack. The cavalry was pushed back from the river.

Krzysztof Korycki and Janusz Tyszkiewicz occupied the right wing, Prince Wiśniowiecki the left. Suchodolski, Osinski's infantry and artillery stood in the centre. According to Wiśniowiecki's plan, it was decided to take advantage of the favourable terrain conditions and use a cavalry charge on the freshly crossed enemy forces.

Krzywonos positioned the stockade together with the Zaporozhian infantry on the right wing facing Korycki, the left wing was occupied by the rest of the army (mainly black). In the centre stood most of the cavalry, some infantry and artillery. Under Cossack artillery fire, the defence of the dragoons guarding the crossing collapsed. The enemy proceeded to make a general crossing. Under the fire of Polish cannons, Krzywonos began forcing the Sluch on his left wing. Wiśniowiecki halted the artillery fire and withdrew his troops, posing as a retreat, thus allowing the Cossacks to cross. When several thousand Cossacks had crossed, the cavalry moved to charge with full force. The enemy, with heavy losses, was driven back across the river in its entirety, and the cavalry, before returning to its previous positions, managed to capture 4 cannons and 2 hook guns from across the river. A similar manoeuvre was repeated three more times.

On the third occasion, the Polish cavalry crossed the Sluch and struck at the Cossack artillery, capturing 9 guns. The Cossack cavalry, which had previously crossed, did not dare to strike at the Polish rear. The Polish army, due to being too outnumbered by the enemy and because of the lack of infantry, which had been sent back earlier, did not attempt to capture the Cossack stockade. Wiśniowiecki decided to retreat to Kolczyn. Krzywonos soon advanced to the other bank of the Sluga and took Konstantinov.