Sangakkara hit six sixes and 18 boundaries in an entertaining innings off 136 deliveries to lift Sri Lanka to a commanding 320 for 5 in 50 overs.
Colombo: Kumar Sangakkara smashed a career-best 169 as Sri Lanka thrashed South Africa by 180 runs for their second heaviest defeat in one-day international cricket on Saturday.
Sangakkara hit six sixes and 18 boundaries in an entertaining 136-ball innings to lift Sri Lanka to a commanding 320 for 5 in 50 overs.
Fast bowler Lasith Malinga dealt a blow to South Africa's daunting run chase with his first ball, bowling opener Colin Ingram with an inswinging yorker for a first-ball duck. The visitors never recovered and lost regular wickets to be dismissed for 140 with 18 overs to spare.
Sangakkara's innings, which won him the player of the match award, was the third best ODI score by a Sri Lankan after Sanath Jayasuriya's 189 in 2000 and Upul Tharanga's 174 not out less than three weeks ago.
He also beat his previous best one-day score of 138 not out against India in 2005. The defeat was South Africa's second heaviest by runs after losing by 182 to Pakistan. It was also Sri Lanka's biggest win over South Africa.
Sri Lanka's Dinesh Chandimal said he was pleased with the win on his captaincy debut. Chandimal will be captain for the first two matches while regular captain Angelo Mathews serves a suspension for a slow over rate in the tri-series final in the Caribbean this month.
"Sanga and Mahela (Jayawardene) are wily old foxes, they know how to do it," he said of the contribution from the senior players.
There weren't many positives to take from the match for South Africa.
"It's not the end of the series, I know my boys will fight back," captain AB de Villiers said.
"We were way below par but I know what the players are capable of, the second game is on the same field, we know the conditions quite well now."
Left-arm spinner Rangana Herath returned the best bowling figures for the hosts with 3 for 25 while seamer Thisara Perera got 3 for 31.
Opener Alviro Petersen, who top-scored for South Africa with 29, shared a promising 44-run partnership with de Villiers for the third wicket but Herath struck with his third delivery, bowling de Villiers for 23. The visitors lost their remaining seven wickets for 67.
Earlier, Sri Lanka were sent in to bat by de Villiers and lost opener Tillakaratne Dilshan with the total on 23. Coming in at No. 3, the left-handed Sangakkara took full advantage of some wayward bowling from the visitors for his 16th one-day century.
Sangakkara shared useful partnerships of 70 for the second wicket with Tharanga who made 43, and 74 with Jayawardene (42). Sangakkara contributed 100 in an 84-ball stand of 123 with Lahiru Thirimanne (17) for the fourth wicket.
Fast bowler Morne Morkel took 2 for 34 in 10 overs but others struggled to maintain direction as Sangakkara played aggressively and improvised, using the bowlers' pace for runs behind the wicket.
Fast bowler Chris Morris went for 80 runs in his nine overs while Ryan McLaren conceded 69 off his 10. Altogether, the South Africans bowled 15 wides. The second of five matches will be at the same venue on Tuesday.