Costa Rica striker Joel Campbell hailed his side's "personality" after they recovered from an opening-day mauling by Spain to beat Japan 1-0 at the World Cup on Sunday.

"Los Ticos" put their 7-0 humiliation by Spain behind them as they launched a smash-and-grab raid on Japan, snatching victory through Keysher Fuller's 81st-minute strike.

Costa Rica came in for fierce criticism in the build-up to the match but veteran Campbell said they never stopped believing they could turn things around.

"Losing 7-0 and then getting back up to beat Japan 1-0 -- only a team with personality can do that," said Campbell, one of four survivors from Costa Rica's run to the 2014 World Cup quarter-finals to start against Japan.

"The result of the first match is something that can happen in football, but the good thing is that there is always a rematch."

Costa Rica defended in numbers against Japan and never looked like threatening until a mistake by defender Maya Yoshida handed them a chance.

Fuller's shot took a deflection and looped up over Japan goalkeeper Shuichi Gonda, giving Costa Rica a goal from their first shot on target at this World Cup.

"Obviously we were in pain after our defeat to Spain but now we have taken a weight of our shoulders," said Fuller.

"We are not the best but we are not the worst either.

"It doesn't matter who scored, the important thing was to score."

Costa Rica now have the chance to qualify for the knock-out round and will face Germany in their final group game on Thursday.

"It won't be easy -- they are former champions -- but I have faith in this team and anything can happen," said Campbell.

"It will be difficult to qualify but we have the will and the courage."