Costa Rica manager Oscar Ramirez has stressed that the Central American country's World Cup "isn't over" following their 1-0 loss to Serbia on Sunday.

Roma defender Aleksandar Kolarov scored the game's only goal on 56 minutes, curling a precise free kick over the wall and beyond the reach of Keylor Navas from 20 yards.

The remaining two games for Los Ticos in Group E involve five-time world champions Brazil and a solid Switzerland side, but Ramirez is not feeling too downtrodden.

"We play against the second and sixth-placed teams in the FIFA rankings," Ramirez told reporters at full time. "It's going to be difficult, but I just told my team: 'This isn't over.'

"We should've capitalised on our opportunities like they did. We had our tactical plan in place and with the subs, we tried to attack them on the wings. We tried to execute our plan but they managed to score on a set piece. What can you do?"

Costa Rica face Brazil in St Petersburg next Friday.