Diadie Samassekou (20 minutes), Diedonne Gbakle (53rd minute) and Aboubabacar Doumbia (81 minutes) scored wonderful goals for Mali to send 2009 champion Ghana packing 3-0 at the Wellington Regional Stadium.
Mali finished Group D in third place but produced the goods against highly fancied Ghana, which had topped Group B.
Group D winner Serbia survived an almighty scare against Hungary at Otago Stadium in Dundelin, with Ivan Saponjic netting a minute into time added to stave off elimination, after Bence Mervo's 57th minute opener.
Milan Gajic found time to receive a second caution to see red before the end of regulation time but if mattered little when, with time fast running out and the game destined for a penalty shootout, an own goal from Magyars substitute Attila Talaber gifted Serbia the win and a spot on the final eight.
United States booked its place in the quarter-finals for the first time in eight years thanks to a Rubio Rubin strike and a heroic Zack Steffen penalty save to help it past Colombia with a 1-0 win.
The Stars and Stripes were on the back foot for much of the game but Rubin's strike in the second half was enough to secure a spot in the last eight, though Jarlan Barrera's effort from the spot had to be kept out with 10 minutes to go as it looked as if he might force extra-time.
Ibrahima Sy saved three penalties as Senegal won a dramatic shootout 3-1 against Ukraine to reach the last eight.
This memorable climax came about after the sides were locked 1-1 at the end of normal and extra time, with Artem Biesiedin's well-worked opener in Auckland having been cancelled out by a late Sidy Sarr leveller.
