The last encounter in this seven-match series was billed as a fond farewell to experienced duo Kumar Sangakkara and Mahela Jayawardene.
The former was playing his final ODI in his home country, while for Jayawardene it was his last match of any description in Sri Lanka.
Yet both were outshone by Dilshan, who, in his 300th ODI appearance, struck 101 in the hosts' total of 302-6, and then took 3-37 from 10 overs as Sri Lanka wrapped up a 5-2 series victory.
Jayawardene and Sangakkara both made starts without going on to get the big score the home crowd yearned for, before Dinesh Chandimal and Thisara Perera made half-centuries to boost Sri Lanka's total
As England toiled in their reply, Joe Root continued his fine form in the series with 80, but his innings proved to be in vain as the tourists fell to 215 all out with more than four overs unused.
Jayawardene (28) and Sangakkara (33) were both afforded standing ovations as they left the field, having become the first and second wickets to fall as England applied the brakes after Sri Lanka had got off to a flying start.
Dilshan looked as though he was about to cut loose when he hit James Tredwell for two fours and a six in successive balls at the end of the seventh over.
However, apart from two more successive boundaries off Harry Gurney later in his innings, the 38-year-old accumulated runs steadily for the most part as he moved beyond 9,000 ODI runs.
Dilshan brought up his 18th ODI century in the 44th over, but was dismissed two balls later when he smashed a full toss from Chris Jordan (2-55) to Moeen Ali on the boundary.
Chandimal (55 not out) and Perera then set about the England bowling attack with abandon, the latter particularly impressive in crashing 54 from 26 balls to give the innings some late impetus.
Under-fire England captain Alastair Cook rode his luck in the early part of his stay at the crease, surviving an lbw shout in the first over before seeing Jayawardene miss two tough chances at slip.
After seeing Moeen fall for a duck and the recalled Alex Hales depart for seven, Cook made it to 32 before edging Suranga Lakmal (2-25) to Jayawardene, who this time took a fine diving catch low to his left.
Cook has now failed to pass 50 in 10 ODI innings.
James Taylor and Eoin Morgan added just six between them as England fell to 78-5, before Jos Buttler (23) stopped the rot to an extent by putting on 48 with Root.
Chris Woakes then contributed 34 to a 66-run stand, but when he and Root fell in consecutive overs the game was up for the tourists.
Jayawardene was thrown the ball by skipper Angelo Mathews in the closing stages and, in a somewhat fitting finale, he and Sangakkara combined to have Tredwell stumped, ensuring they signed off in Sri Lanka with a convincing victory.