Multiple goal victories saw the Spanish, African and Arabian sides advance out of the group stage, while Costa Rica took a big stride towards qualification as they edged AustraliaGroup C
Ecuador 0-2 Spain
After being held scoreless for more than an hour, Spain overcame Ecuador to earn a 2-0 win and seal qualification for the Under-20 World Cup knock-out rounds.
Both sides had their share of chances in the first half, with Spain's Koke being denied by an excellent save and Ecuador's Gaibor having his attempt deflected just wide. Rodrigo had a clear chance to put the Europeans ahead, but failed to convert with the goal open.
The introduction of Sergio Canales on the hour mark proved decisive, as nine minutes after his substitution the talented forward tapped into an open net from Tello's assist. Canales then played Alvaro Vazquez through on goal, and the Espanyol man made no mistake as he made it 2-0 in the 85th minute.
Following their loss, Ecuador head into their final match needing a result against Costa Rica, while Spain qualify for the round of 16 with a flawless record which they will hope to keep in tact when they meet Australia.
Australia 2-3 Costa Rica
Costa Rica rebounded from their recent loss to Spain as they edged past Australia. The Socceroos were strong in the opening stages, but Joel Campbell's clinical finishing made the difference on the day.
After a trio of missed opportunities from Australia, Campbell cleverly made space before firing home the opener on 22 minutes. It took just four minutes for the Aussies to equalise, thanks to a lunging redirection by Tommy Oar. Seconds after the restart, Campbell restored the Ticos' lead as he netted a fine strike on the half-volley.
For a second time Australia equalised, albeit under fortuitous circumstances. In the 64th minute, Francisco Calvo botched a clearance attempt, redirecting the ball into his own net. The Young Socceroos looked the better side late, but Costa Rica were again first to score against the run of play. In the 72nd minute, John Ruiz finished from Campbell's corner, earning three points for the Central American side.
The result sees Costa Rica take a masive stride, though they will need a result against Ecuador in order to qualify. Australia's situation is just the opposite; Jan Versleijen's side need a win against Spain if they are to advance.
Saudi Arabia 6-0 Guatemala
Saudi Arabia continued their fine run of form as they inflicted a veritable hammering upon Guatemala. The Green Falcons took little time to find themselves on the scoreboard, with Yahya Dagriri scoring the opener on 17 minutes. Yasir Alfahmi added a second 10 minutes later, and the Saudis carried the lead into half-time.
Quick-fire goals from Mohammed Alfatil (58') and Yasir Alshahrani (66') doubled the lead, leaving Khalid Alkoroni's side well in control of the match. Ibrahim Alibrahim (83') and Salem Aldawsari (89') added late strikes to round off an emphatic victory.
The result sees Guatemala eliminated, while Saudi Arabia qualify for the knock-out rounds with Nigeria to come in their final group game to decide who tops the pot.
Croatia 2-5 Nigeria
A strong performance over the last half hour saw Nigeria keep pace with Saudi Arabia in Group D, as the Flying Eagles earned a 5-2 win over Croatia. The Blazers made good use of their few chances, but were ultimately undone by a Nigeria side that dominated the match overall.
Olarenwaju Kayode (25') and Terna Suswan (30') gave the Green Eagles a commanding lead early, but Ivan Lendric pulled a goal back for the efficient Croats three minutes before half time.
After Ahmed Musa made it 3-1 on 62 minutes it appeared that Nigeria were well on their way to three points. Andrej Kramaric struck four minutes later to put the Europeans back in contention, but his strike would prove to be in vain. Uche Nwofor restored Nigeria's two-goal advantage on 69 minutes, and made it 5-2 in the 73rd minute.
Nigeria held on to secure qualification for the round of 16, while Croatia's loss left them needing a win against Guatemala to have a chance of advancing.