Norway 0 New Zealand 2
Wellington Phoenix defensive midfielder Gianni Stensness scored a screamer to open the scoring in the 71st minute before an own-goal from Norway's John Kitolano wrapped up the 2-0 victory.
It's the third consecutive under-20 World Cup that the Kiwis have qualified for the Round of 16.
Stensness' teammate at Wellington, Liberato Cacace was in sensational form in a dominant performance by the junior All Whites.
Honduras 0 Uruguay 2
Uruguay opened the lead in the 41st minute through a smart set-piece.
Brian Rodriguez chipped a free-kick on to the head of Sebastian Caceres who flicked the ball tantalisingly across the face of goal, allowing Acevedo to blast the ball into the back of the net.
The victory was sealed by the excellent number 10, Nicolas Schiappacasse, who struck in added time.
USA 2 Nigeria 0
Hannover 96 striker Sebastian Soto struck twice for the United States in their impressive win over Nigeria.
The 18-year-old striker head home a corner in the 18th minute and then doubled his country's lead just one minute after half-time with a well-taken goal.
Qatar 0 Ukraine 1
Ukraine are into the last 16 of the tournament thanks to Denys Popov's headed from a corner in the 59th minute.
Qatar's misery was compounded in the 85th-minute when captain Nasir Peer was shown a straight red card for a late tackle on Maksym Chekh.