Japan's second-round hopes at the Under-20 World Cup will rest on their final Group D game against Italy after Atsushi Uchiyama's side lost 2-0 to Uruguay on Wednesday.

Nicolas Schiappacasse and Mathias Olivera scored on either side of the break for Uruguay, who booked a spot in the knockout phase with their second win in as many games.

With Italy defeating South Africa 2-0, Japan dropped to third place behind Italy on goal difference. Japan must beat Italy in Cheonan on Saturday to reach the round of 16.

"The result is disappointing, that's a fact," Uchiyama said. "I thought from the second half we adjusted and started playing the football we're capable of."

"We have to regroup for the next one right away."

Uruguay qualified for this tournament as the top team from South America and showed their class, threatening Japan time after time behind their strong physical game.

In the 11th minute, Nicolas de la Cruz robbed Takehiro Tomiyasu at the back for a one-on-one with goalkeeper Ryosuke Kojima, but the Uruguayan striker blasted wide of the left-hand post.

Japan took an unexpected hit in the 20th minute, when Koki Ogawa, who scored in Sunday's 2-1 win against South Africa, landed awkwardly on his left foot and was stretchered off the pitch.

Ogawa was replaced by 15-year-old Takefusa Kubo, who demonstrated once again that he belongs at this age group with his poise and an understanding of the game far beyond his years.

But it was the Uruguayans who broke the deadlock in the 38th minute, Schiappacasse netting into the bottom left corner amid congestion in the box to give the South Americans the halftime lead.

Two minutes to the hour, Kubo stung the palms of Santiago Mele with a ferocious shot from an angle. Ritsu Doan was first to the deflection, but headed straight at the keeper, who denied the Gamba Osaka man.

Uchiyama's men continued to make Uruguay work but in the 91st minute, Olivera hit past Ryosuke Kojima to finish an overlap down the left wing, killing Japan off in the process.

With Ogawa questionable for the Italy game and having slid down the table to third, Japan will have their work cut out for them on Saturday.

"We have to learn from this and give it everything we have in the next match," captain Yuta Nakayama said.