The victory left Serbia on four points from two games after Saturday's goalless stalemate in Scotland, which came on the back of three defeats and a draw in friendlies.
Having come under fire for tepid performances which produced only one goal in five games, Mihajlovic reshuffled his youthful team and the tactic paid dividends in Vojvodina Novi Sad's acoustic Karadjordje stadium in front of a capacity 15,000 crowd.
Kolarov fired the home side ahead when he curled a delightful free-kick from 18 metres over the wall past the despairing dive of Wales goalkeeper Boaz Myhill in the 16th minute.
The Manchester City player turned provider eight minutes later after muscling his way past two defenders to the touchline and squaring the ball for Serbia captain Zoran Tosic to steer it home from close range.
Tottenham Hotspur midfielder Gareth Bale, who started on the right flank but quickly switched to the more familiar left, gave a colourful band of 500 Welsh fans something to cheer about when he halved Serbia's lead with a brilliant free-kick.
His stinging and swerving shot from 25 metres left Serbia keeper Vladimir Stojkovic rooted to his line as it almost ripped the netting in his top right corner, but Welsh joy was short-lived as Serbia quickly restored their two-goal advantage.
A pair of 20-year olds carved the visitors open with a slick move as winger Dusan Tadic released Filip Djuricic with a lovely through ball and the striker buried his shot into the roof of the net after rounding Adam Matthews.
Serbia continued to have the upper hand after the break and their incessant attacks soon bore fruit as Chelsea defender Branislav Ivanovic raced down the right flank and delivered a perfect low cross for Tadic who swept the ball past Myhill.
Ivanovic capped his own outstanding performance in the 80th minute with a rasping low shot from the edge of the box with his weaker left foot to delight the home fans who sang incessantly to the beats of a giant drum.
Substitute Miralem Sulejmani, making his first appearance after recovering from a long-term injury, put the icing on the cake in the 90th minute with a deflected effort from 20 metres which caught Myhill stranded.
Serbia's next two games are at home to Belgium on October 12 and away to Macedonia four days later. Wales are at home to Scotland before they visit Croatia.
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