"It is great to have three points in the bag, but we are not finished. I don't want to do the maths yet", Kolarov said.
In the photo, Valeria Zuluaga shows the comfort with which she will be enjoying the game early Sunday morning at the Costa Rica Beer Factory.
Krstajic, a former Serbian worldwide defender, has called on plenty of experience, though, with former Chelsea centre-back Branislav Ivanovic, Roma defender Aleksandar Kolarov and Manchester United midfielder Nemanja Matic all starting.
Milinkovic-Savic spent the bulk of the first half shouting because he didn't get the ball where he wanted it, and too many crosses missed the mark because the intended target took a different route. The fitness of the player is in doubt but the team however will depend on his ability to score find the net. But a narrow, one-goal win over a Costa Rican team that came into the World Cup in poor form is hardly cause for celebration, and the match highlighted a key weakness in the side.
Serbia finally broke the deadlock when Aleksandr Kolarov unleashed a scorching free-kick from 30-yards that gave Navas no chance on 56 minutes.
Bunjevcevic, 45, played for the national team from 1998-2003, appearing in 16 matches.More news: PM says £20bn cash boost for NHS 'must be invested in technology'
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Costa Rica advanced out of the group stage in Brazil with victories over Uruguay and Italy and a draw with England, but the country's players insisted in the run-up to Sunday's game that this team should not be judged on the past.
Despite being flagged for offside it was Milinkovic-Savic who produced the moment of the first half when he directed an overhead kick goalwards. Free-kicks are proving rather more successful at this World Cup than the one in Brazil four years ago.
In a bad position after losing, Costa Rica will quickly need to pick themselves up ahead of their second game - against tournament favourites Brazil in five days' time. The goal wouldn't have counted, as Milinkovic-Savic was offside, but it was a attractive effort nonetheless.
"From what I have seen in the locker room, I think that we still believe in our opportunities", stressed Ramirez, who took over as head coach in the wake of the last World Cup.