World Cup Under-20 hosts Turkey have started their campaign with a flawless 3-0 victory over El Salvador in Group C.
Cenk Sahin was the hero for the home favourites, scoring a second-half double to end the resistance of the outclassed Central Americans.
Fenerbahce midfielder Salih Ucan gave the Turks a ninth minute lead, but they were made to wait until the 46th minute before easing the nerves with a second goal.
In the other match, Australia held out against South American champions Colombia before succumbing to a 1-1 draw.
The youngest player at the tournament, Perth Glory's Daniel De Silva, stunned the Colombians just after the break, but Jhon Cordoba hit back with 12 minutes left on the clock and the two nations were forced to share the spoils.
Meanwhile in Group D, Greece snatched a late winner to stun Mexico 2-1 in their opening match.
Andreas Bouchalakis gave the Greeks the lead in the 16th minute, only for the Mexicans to draw level through Jorge Espericueta just before the break.
But attacker Dimitrios Kolovos claimed all three points for Greece with a strike two minutes from time.
Paraguay and Mali rounded out group with a 1-1 draw, both goals coming in the early minutes of the match.
Mali's Adama Niane opened the scoring in just the third minute only for Benfica player Jorge Rojas to hit back four minutes later.