Costa Rica rebounded from a 7-0 thrashing by Spain with a 1-0 win over Japan as the Qatar World Cup served up another surprise on Sunday.
Japan gave the ball away cheaply in the final third and Keysher Fuller curled in the winner on 81 minutes, but goalkeeper Shuichi Gonda should have done better.
Japan's strangely insipid performance followed their heroics in beating Germany 2-1 in their opener. Their defeat means Germany will still be in contention even if they lose to Spain later Sunday.
A win for Japan would have put them on the cusp of qualification for the last 16 but they failed to create any meaningful chances for much of the contest.
Yuki Soma's wayward free-kick was arguably the closest Japan came.
Costa Rice are not out of the last 16 picture either after their battling display, surviving a late onslaught from Japan to prevail.
