Aleksandar Kolarov quality the difference as Serbia do enough to beat Costa Rica

SAMARA, Russia -- Three quick thoughts in Serbia's 1-0 win over Costa Rica in Group E at the World Cup on Sunday.

1. Aleksandar Kolarov quality proves the difference

Serbia are up and running. While this match was no classic it contained a goal fit for any World Cup game, curled in beautifully by Kolarov in the 56th minute, and that free kick was enough to beat a decent but ultimately limited Costa Rica side.

It gives Serbia a boost going into their potentially decisive meeting with Switzerland, while Costa Rica's hopes of progress already look bleak with Brazil up next.

Costa Rica began with menace. Less than two minutes had passed when Marcos Urena, sent scuttling free on the right of the penalty area by Bryan Ruiz, forced Vladimir Stojkovic to block at a tight angle. Giancarlo Gonzalez planted a header at the Serbia keeper moments later and the early exchanges took on a brisk, open feel.

A much easier chance fell Gonzalez's way in the 12th minute and he was left shaking his head. David Guzman's precise cross invited a simple header past Stojkovic from six yards but instead the centre-back, seemingly getting his timing wrong, headed well over.

Gradually Serbia, the prematch favourites, assumed a measure of control but clear chances were few. An Kolarov free kick was punched clear by Keylor Navas, who also tipped a Branislav Ivanovic cross away -- while Sergei Milinkovic-Savic, volleying a cross-shot wide, exerted some influence. But Costa Rica remained lively, Urena and the left wing-back Francisco Calvo both shooting off target after smart approach play as half-time neared.

Serbia came out with increased urgency in the second half and made it tell. They came close when Aleksandar Mitrovic, running onto a delightful ball from Milinkovic-Savic, was denied by Navas but the breakthrough would come moments later.

It was a goal worth waiting for: Few people can strike a left-footed dead ball like Kolarov and, given the opportunity to go for goal 25 yards out, he produced one from the textbook. He sent the ball curling at some speed past a full-stretch Navas.

Serbia, at last looking a side befitting of their ability, were on their way. They might have scored more, Milinkovic-Savic shooting over and the substitute Filip Kostic somehow fluffing his lines in front of the net.

2. Milinkovic-Savic provides glimpse of lavish talent

If there was one particularly appetising element to this game, the least glamorous of Sunday's three on paper, it was the chance to see Milinkovic-Savic on the highest stage of all.

The Lazio playmaker has been strongly linked with a big-money transfer to Manchester United or Real Madrid but is largely an unknown quantity at international level. This was only his fifth cap, owing more to previous manager Slavoljub Muslin's tactical preferences than any lack of aptitude, and Serbia have made little secret that he is the man they want to construct their team around. Even on this relatively low-key afternoon, it was easy to see why.

In a disappointing first half, Milinkovic-Savic was Serbia's most compelling player, showcasing a remarkable ability to retrieve seemingly lost situations through telescopic legs and slick footwork. One burst beyond the defence brought a good chance and a save from Navas, although Milinkovic-Savic was ruled to be offside; later on he was flagged again when forcing the Real Madrid keeper to repel a smart overhead kick. The second of those decisions was given incorrectly and the sequence was evidence of the invention and spontaneity Milinkovic-Savic adds to a sometimes uncertain team.

After the break he teed up that chance for Mitrovic and continued to drive Serbia forward. This was by no means a vintage performance from player or team but it still augured well. This is a young Serbia side whose manager, Mladen Krstajic, had not coached a senior team before this year; they are still learning his ways and also those of their new talisman on the field.

It will take time and, logically, the expectation is that they will only improve. Dusan Tadic can produce more than he did here and Mitrovic, so lethal in England with Fulham, should have scored at least once. The feeling with Serbia is that there is a devastating team bursting to get out: whether or not they can do it in Russia is moot but for them, and Milinkovic Savic, this was a good enough start.

3. Costa Rica's competence not enough

Costa Rica's chances of repeating their quarterfinal finish of 2014 look slim now. This was by no means a poor performance from Oscar Ramirez's side, but they will regret that big early miss from Gonzalez, which would have tested Serbia's often-fragile mental resolve to the limit.

It can sometimes be too easy to place teams in convenient brackets. Costa Rica, with their five-man back line and lack of stardust, had been billed as a dour defensive outfit in some quarters before the tournament kicked off. That does them a disservice: they played with intelligence, committing men forward in good numbers when appropriate but also repelling Serbia in relative comfort for the majority of the game.

Their wing-backs, Calvo and Cristian Gamboa, supported the attack well and Costa Rica looked what they were four years ago: a compact, well-drilled team that does everything to a fairly high standard.

That is not likely to be enough this year. In truth they lack an attacking spearhead of genuine quality and are not quite creative enough either, despite the best efforts of the willowy Ruiz. Most of their more threatening moments came from set-pieces, where Gonzalez and his central defensive partner Oscar Duarte posed a threat and caused a number of goalmouth scrambles. From open play, there was never quite the right final pass or delivery.

They will have earmarked this game as one to win if a place in the round of 16 was to be achieved. Next up is a date with Brazil and the sense is that it will take a sensational result -- and performance -- to continue their interest in this competition now.