Poland lost 2-0 to Colombia in their first game of the FIFA Under-20 World Cup which is taking place in the Eastern European nation.
Iván Angulo scored in the 23rd minute at Stadion MOSiR before Luis Sandoval converted in the last minute to confirm Colombia's victory.
They join Senegal at the top of Group A after the African nation beat Tahiti 3-0 thanks to a Amadou Sagna hat-trick.
Italy got off to a winning start in Group B, defeating Mexico 2-1.
Davide Frattesi was on the scoresheet for Italy within three minutes, Roberto de la Rosa equalising for Mexico just before half-time.
Luca Ranieri grabbed the winner for his team in the 67th minute.
The remaining Group B clash between Japan and Ecuador ended at 1-1.
Japan's Kyosuke Tagawa scored an own goal, before Koto Yamada brought the fixture level.
The competition will continue tomorrow with Honduras taking on New Zealand and Uruguay meeting Norway in Group C.
Qatar play Nigeria, before a match between the Ukraine and the United States ends the day.