Ajantha Mendis' international career has been almost as vexing as his variations themselves. Hyped as the next Muttiah Muralitharan while Murali was still playing, Mendis painted a target on his back with a phenomenal first 18 months at the top level. When he was a debutant in Port of Spain, West Indies batsmen wondered whether they would ever decipher him, given they couldn't even pick his variations on the slow-motion replay. In the Asia Cup two months later, Mendis was by far the highest wicket taker, having inflicted a gobsmacking 6 for 13 to ruin India in the final. In three home Tests that followed, he plundered 26 wickets at 18.38 against supposedly the best players of spin bowling.

Yet as emphatic and immediate as his success was, his aura diminished just as quickly in the next phase of his career. Batsmen from the subcontinent rallied the resistance - first Pakistan, who were un-flummoxed by him in two Tests in Sri Lanka, before India sniped back at their old tormentor in another Test series in India. Soon England, Australia and even New Zealand were managing his threat. The hauls began to grow lighter, the runs flowed more freely, and with Murali also dimming towards the end of his career, Sri Lanka's spin attack suddenly lost its bite. Mendis had become the quickest bowler to 50 ODI wickets, managing that feat in 19* matches. In 40 games since, he has added only 46 scalps to that tally. In all formats combined, the three years since that initial 18 months have only yielded him 32% of his wickets - though that is in part due to fewer opportunities, which in turn is largely the result of poor form.

Still, despite the dive in ODI and Test results, Mendis has remained a threat in Twenty20s. Last year against Australia in Pallekele, Mendis took 6 for 16 in a match-turning spell, to record the best figures in the format. He has now bettered that with 6 for 8 in the World Twenty20 opener against Zimbabwe. His average of 9.84 and economy rate of 5.45 are the best of any bowler to have taken more than 25 wickets. There are no major changes to Mendis' game, but in a format where batsmen need to be aggressive, his fingers seem to retain their old charm. It is something his captain seems aware of, when he routinely brings him on in the Powerplays.

Hamilton Masakadza found out how difficult Mendis is to attack when he attempted to swipe one away to the legside, but misread the turn completely, and had his stumps rattled by a googly that slotted in nicely between bat and pad.

"He gives you very little to score off," Zimbabwe captain Brendan Taylor said. "When you're chasing nine an over you have to go after some bowler. He was on top of his game tonight and probably caught us off guard a bit."

Earlier, Vusi Sibanda was bowled by Mendis' straighter one, before Taylor himself was undone by the carrom ball. Elton Chigumbura attempted a similar shot to Masakadza, and succumbed in almost identical fashion to the same Mendis delivery. The harvest might have become leaner in other formats but here Mendis' full house of trickery still reigned supreme, even if this was his first game after a long layoff due to a back injury.

"Ajantha was very keen to get back into the side and we saw that hunger in him," the Sri Lanka captain Mahela Jayawardene said after the match. "Even in the domestic tournament [SLPL] he came back and bowled really well. That was the indicator to see how match fit he was and how much control he had. This was his first game in eight months and he was a bit nervous before the game but he bowled really well."

Mendis' real tests will come against opposition who will have studied him more closely on video, and are better equipped with the batting tools to read him more accurately than Zimbabwe did. South Africa will provide the initial examination on Saturday.

"He's comeback strongly and hopefully he'll continue to do the job," Jayawardene said. "I'm sure he'll have bad days but the quality of the player is that he'll have more good days than bad."

The theories to explain Mendis' recent woes in the longer formats are many. He has not bowled a wicket-to-wicket line, some say, and when he strays he goes blunt and is easy to pick off. Others say the mystery has expired. Teams have simply worked him out, and since Mendis is not a spinner who relies on flight, dip or extravagant rip, once the batsmen know which way it will turn, he loses his effectiveness. Still others have suggested batsmen have succeeded in playing him as a seam bowler, like they did to Anil Kumble (though if this was all it took to unhinge both bowlers, it would have been worked out earlier in Mendis' career, and Kumble would not have finished with 619 Test wickets).

Can Mendis prove he can still be a force for Sri Lanka with more fine spells in the tournament? His career at large needs a serious boost, and though he may never be the bowler his initial surge suggested, he will hope he can use his favourite format as a launching pad to success in others.

*04:34 GMT, September 19: The article had incorrectly stated 17 matches. That has been changed.