World Cup 2018, Costa Rica vs Serbia: This win puts Serbia in a strong early position in Group E ahead of games against Brazil and Switzerland
Serbia coach Mladen Krstajic handed Branislav Ivanovic his 104th international appearance, making the former Chelsea centre-back the most-capped player in his nation's history, moving clear of Dejan Stankovic in the all-time list.
Costa Rica started brightly, with Vladimir Stojkovic diving to save at the feet of Marcos Urena, before Giancarlo Gonzalez headed straight at the Serbia goalkeeper.
The Central Americans should have taken the lead in the 12th minute, but Bologna defender Gonzalez inexplicably headed over when unmarked at the back post with the goal at his mercy.
Serbia grew into the game and started to dominate possession, with Costa Rica playing in the same style which brought them so much success in 2014, sitting deep and looking to pounce on the counter-attack.
Sergej Milinkovic-Savic, whose non-selection during qualifying led to Slavo Muslin's sacking as Serbia coach, almost broke the deadlock on the stroke of half-time, but his overhead kick was well kept out by Real Madrid 'keeper Keylor Navas in the Costa Rica goal.
Serbia did take the lead in the 56th minute, though, and in fine style.
The 32-year-old Kolarov fired a sublime left-footed free-kick over the wall, dipping into the top corner past a despairing dive from Navas.
Coach Oscar Ramirez threw on Arsenal forward Joel Campbell, Costa Rica's star player in Brazil in 2014, in search of an equaliser.
Campbell's speed almost got him in behind the Serbia defence just seconds after coming on, but it was Serbia who blew a gilt-edged chance to score a second.
Dusan Tadic's low cross picked out Filip Kostic, but the substitute miskicked in front of an open goal, perhaps due to a slight touch on the ball by Navas.
There was a late scuffle as Nemanja Matic tried to take the ball off a member of the Costa Rican staff on the sidelines, before a VAR red-card review saw Aleksandar Prijovic booked for a separate incident, but Serbia held on with relative ease for a potentially priceless win.