Pinamonti chipped goalkeeper Radoslaw Majecki  with his 38th-minute spot-kick after Dominic Steczyk's handball.

Poland's best chance to equalise came shortly after half-time, when Italy keeper Alessandro Plizzari saved one-on-one from Marcel Zylla.

The hosts pushed hard but could not find an equaliser in Gdynia, although their run to the last 16 matched their best Under-20 World Cup performance in 2007.

Italy will play either Argentina or Mali in the quarter-final on July 7 in Tychy.

In the later kick-off at Lodz Stadium, Colombia fought their way past New Zealand via a penalty shootout following a 1-1 draw after extra time.

Colombia opened the scoring against the run of play on 11 minutes after Andres Reyes glanced a header inside the far post from a free kick.

But New Zealand equalised 10 minutes before halftime when Elijah Just poked home Liberato Cacace's low cross.

In the shootout, Kiwi goalkeeper Michael Woud saved the first two Colombian penalties and appeared to have denied three in a row before the referee ordered a retake.

Colombia recovered to send the shootout to sudden death and edged to a 5-4 success when Matt Conroy had his effort saved by Kevin Mier.

The South Americans face either Ukraine or Panama next.