Skipper Dasun Shanaka hailed Maheesh Theekshana as a top prospect after the debutant spinner helped Sri Lanka thrash South Africa by 78 runs to clinch the one-day series 2-1 on Tuesday. Theekshana, an off-spinner with a lethal carrom ball, returned figures of 4-37 as the hosts bowled out South Africa for 125 in 30 overs while chasing a target of 204 in the third ODI in Colombo. The 21-year-old Theekshana made an instant impact with a wicket on his first delivery in international cricket as he sent opener Janneman Malan trudging back for 18. Rain then briefly stopped play. He then cut short wicketkeeper-batsman Heinrich Klaasen’s innings on 22 to further dent the Proteas’ chase. “Theekshana was our trump card,” Shanaka said after the win. “He’s more of a T20 bowler but I used him wisely in this match. He’s a real prospect going forward.” Andile Phehlukwayo, who made 17, and George Linde, who scored 18, put up some resistance with a partnership of 36 for the seventh wicket. Theekshana combined with leg-spinner Wanindu Hasaranga, who took two wickets to polish off the tail with 20 overs remaining in the innings. Pace bowler Dushmantha Chameera took two early wickets including Reeza Hendricks, for one, and Rassie van der Dussen, for five, to rattle the South African top-order. He also made a useful 29 in Sri Lanka’s 203 for nine to be named man of the match. Sri Lanka’s Charith Asalanka top-scored with 47 while Keshav Maharaj claimed three wickets. Maharaj struck first, getting Avishka Fernando lbw for 10, and returned figures of 3-38 with his left-arm spin. Fellow spinners Linde and Tabraiz Shamsi took two wickets each. South Africa successfully reviewed the openers’ wickets in their favour after Fernando and Dinesh Chandimal, out lbw for nine off left-arm orthodox Linde, were given not out by the on-field umpires. Spinners kept striking as Aiden Markram sent back Dhananjaya de Silva for 31 and Maharaj got two, including Shanaka and Hasaranga, as Sri Lanka slipped to 121-6. Asalanka survived a reprieve on 36 when he was caught at mid-wicket off Linde but the delivery was adjudged a no ball with more fielders outside the inner circle than allowed. Shamsi, a left-arm wrist spinner, finally got Asalanka caught behind to deny the left-hand batsman a half-century. “Today our plans weren’t up to scratch, but lots of positives to take,” said Maharaj, who took over as ODI captain from the injured Temba Bavuma from the second match. “We’ve got a few of our senior players back for the T20Is so hopefully that’ll give us the boost we need.” The two sides will now play three Twenty20 internationals starting Friday at the same venue.