Tillakaratne Dilshan and Upul Tharanga put on a World Cup record opening stand of 282 as Sri Lanka became the first team to qualify for the quarter-finals with a 139-run victory over Zimbabwe.
Dilshan hit 144 and Tharanga 133 as the co-hosts piled up 327-6 after being asked to bat at the Pallekele International Stadium.
The partnership, four short of the ODI record for the first wicket, was not broken until the fourth ball of the 45th over when Tharanga holed out off Chris Mpofu's bowling.
Tharanga had largely played the supporting role during his 10th one-day hundred but nevertheless found the boundary 17 times.
Dilshan had attacked right from the start, dispatching three fours and a six to take 18 from the second over of the day, bowled by Tinashe Panyangara (0-51).
Having reached his ninth one-day century in 95 deliveries, the right-hander was out miscuing Prosper Utseya's spin (1-50) high in the air the over after Tharanga
And Sri Lanka lost a flurry of late wickets in pursuit of quick runs, paceman Mpofu finishing with 4-62.
Zimbabwe's openers also made a strong start, Brendan Taylor (80) and Regis Chakabva (35) bringing up a century stand of their own inside 17 overs.
But Chakabva's dismissal, bowled by Muttiah Muralitharan in the 20th over, was the start of a collapse from 116-0 to 188 all out.
Dilshan also enjoyed himself with the ball, narrowly missing out on a hat-trick on the way to career-best figures of 4-4 from three overs.
After removing Craig Ervine lbw for 17, Greg Lamb followed next ball to a brilliant one-handed slip catch from Mahela Jayawardene, who had to move low and to his left.
And spinner Dilshan found the edge of Graeme Cremer's bat with his hat-trick delivery, only to see an easier low chance go through Jayawardene's hands just above the turf.
Last man Mpofu was bowled by Muralitharan as Zimbabwe's were all out in 39 overs.
Sri Lanka are top of Group A with seven points from five matches, while Zimbabwe sit fifth with two points from four games and their quarter-final hopes are fading fast.