Costa Rica defender Johnny Acosta was dazed after being caught by an accidental elbow from Dusko Tosic, but both were able to continue before, with the first half approaching its final five minutes, Urena blasted over from the edge of the box.
That was to prove the only goal of a fractious and largely ho-hum affair.
With a curling free kick that decided the outcome of the match, Aleksandar Kolarov immediately drew some comparisons to Cristiano Ronaldo.
Upon landing, the Serbians were still on top - the result of their first win to open a World Cup in 20 years.
Here's hoping things start opening up a bit as the group stage progresses.
Serbia's attacking players had a field day against a struggling Los Ticos defence, which was set up as a back three - with the wing-backs often leaving their flanks exposed at times.
"We are going to forget Costa Rica now and move forward", Krstajic said.
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Police said they had been called to reports of an explosion and people running at Southgate station at 7:03 p.m. (1803 GMT). Police add that the explosion "appears to have been minor", with no serious injuries believed to have occurred.
Kolarov's tally was what all Serbia needed to carve out a close win, grabbing all three points to take the early lead in Group E. Serbia has three points, Brazil and Switzerland have one point each while Costa Rica has no point to show so far.
The margin of victory would have been greater had Navas not narrowed the angle to deny Newcastle striker Aleksandar Mitrovic after he had been sent clear by the impressive Sergej Milinkovic-Savic earlier in the game.
In the 57 minute Serbia finally broke the deadlock when Kolarove curled a 24-yard free-kick into the top corner of the net, 1-0.
"We want to relay this message to him and his family that we are 100 percent behind him", Koralov said.
No doubt, at least one player of the national team of Costa Rica any more or less knowledgeable football fan, of course, knows.
Kerr was working on Serbia's game against Costa Rica on Sunday afternoon.
The Costa Rican bench were not impressed with the Serbian's vigorous efforts on the sideline. The goal wouldn't have counted, as Milinkovic-Savic was offside, but it was a attractive effort nonetheless.
In the first of the Group E fixtures, potential surprise outfit Costa Rica will take on a talented Serbia side who saw off Bolivia 5-1 in a warm-up match last Saturday.