Guitarist Josh Klinghoffer covered the late grunge icon's Singles soundtrack.
The band's headline slot at the Polish festival clashed with the country's Euro 2016 match against Portugal.
Red Hot Chili Peppers sang a Polish football chant at Open'er festival last night (Thursday 20 June).
According to NME, bassist Flea led the sporting tribute at their headline slot at the Polish festival, which clashed with the country's Euro 2016 football match against Portugal.
Unfortunately for Polish fans, their nation didn't get the result they wanted, crashing out of the Euro by losing 4:5 to Portugal on penalties.
The band played a storming set of their biggest hits, which started with Californication and ended with Give It Away.
Watch the crowd sing-a-long to their Otherside below:
See Anthony Kiedis and co. perform The Getaway from their new album of the same name.
See the band's setlist below:
Meanwhile Chad Smith spent his time in Europe wisely, taking time to visit London's Trafalgar Square for a spot of busking.
Video posted by Red Hot Chili Peppers Uruaguy sees the long-time Chilis drummer perform alongside street artists outside The National Gallery.