Japan's players were booed off the pitch Wednesday after losing 3-0 to Serbia in a World Cup warmup match in Osaka.
Dragan Mrda's two first-half goals gave Serbia a comfortable lead and midfielder Nemanja Tomic put the game out of reach at the hour mark with a free kick from 30 yards out.
Japan coach Takeshi Okada and Serbia counterpart Radomir Antic used the game to give younger players a chance to make their case for World Cup selection.
But Japan's fans were not pleased with their team's efforts, jeering the players as they walked off at the final whistle.
"A match at a time like this is difficult for all the players and we also had some injuries," Okada said. "But whatever game it is, the players are representing Japan and I think they needed to dig a bit deeper, especially when we were losing. We lacked spirit."
Mrda opened the scoring in the 15th minute, taking a pass from captain Radosav Petrovic and beating Japan goalkeeper Seigo Narazaki with a left-footed shot from just inside the area.
The Serb forward doubled the lead eight minutes later when he picked up a loose ball in the six-yard box and calmly fired past Narazaki.
"This was a good result for us," Serbia assistant coach Radovan Curcic said. "All the players we brought here are from domestic leagues but they have shown that they will be competing for a place on the team against the regulars in the near future."
Japan's best chance came in the 58th minute when substitute Naohiro Ishikawa broke free but shot straight at Serbia goalkeeper Zeljko Brkic. Tomic rounded off the scoring minutes later with a free kick.
Serbia is in Group D at the World Cup with Germany, Ghana and Australia while Japan has been drawn in Group E with the Netherlands, Denmark and Cameroon.