Slovenia ended Poland's 100% record in the Euro 2020 qualifiers when goals from Aljaz Struna and Andraz Sporar gave them a shock 2-0 win over the Group G leaders on Friday.
Poland had not even conceded a goal in the section heading into the game but their defensive wall was finally breached in the 35th minute, just as they seemed to be taking control.
Sporar flicked on Josip Ilicic's corner and Struna stuck out a leg at the far post to divert the ball past Lukasz Fabianski.
The Poland keeper did well shortly afterwards to turn away Benjamin Verbic's back-flick as Slovenia, who had won only one of their previous 12 competitive games, continued to press.
Striker Robert Lewandowski made a record 107th appearance for Poland, although this was later equalled by Jakub Blaszczykowski when he came on in the 70th minute.
Slovenia had doubled their lead five minutes before that with a breakaway goal after with a throw-in in their own half.
The hosts moved the ball quickly upfield and Sporar ran onto Ilicic's pass, outpaced the Polish defence and beat Fabianski from a tight angle.
Poland are top with 12 points from five games, three ahead of Austria who thumped Latvia 6-0, while Slovenia are a further point behind in third. The top two teams qualify for Euro 2020.