Sebastian Bialoskorka, Arkadiusz Michalczyk, Karol Narojczyk and Kacper Pilarz scored for Polonia with Jake Sansby (2) and Joseph Kelly replying for City. Artur Blaszczyk of Polonia and Gavin Elliott of City were sent off.
Polonia are now second behind Netherton United Reserves who suffered a shock 2-1 defeat at Stamford Bels Reserves. City are sixth, but have games in hand on all the teams above them
Stilton United are back within a point of Peterborough Premier Division leaders Uppingham after a hard fought 3-2 win over Wittering Premiair. Ashley Brand, Kyial West and Matt Barber scored for Stilton.
Uppingham’s scheduled fixture was postponed. They have a game in hand on Stilton who travel to Leverington on Saturday (December 11), when Uppingham host Oundle.
Third-placed Holbeach Reserves are a further eight points behind after losing 3-0 at Oundle Town.
Netherton United came from 2-0 down to draw 2-2 with Stamford Bels at the Grange. Zack Fisher scored both goals for Netherton on his return from injury after Nathan Law and Scott Toomey had scored for Bels.
In Division Three Dreams won for the first time this season as two Kyle Gray goals secured a 2-0 success at King’s Cliffe.
In Division Four Michael Uff scored twice as second-placed Thorpe Wood Rangers beat Rippingale & Folkingham 3-2 to record a ninth win in nine matches. Ethan Bennett scored the other goal.