The big-hitting Gayle blasted nine fours and seven sixes in front of his home crowd to make an easy work of the 209-run target at the Sabina Park.
This was Gayle's 21st ODI ton and third on this ground, the previous one coming against New Zealand last year.
Even as Gayle got out after bringing his side to the doorstep of victory -- the West Indies needed just 28 runs for win in 19 overs -- they lost two more wickets after the Jamaican's dismissal.
After helping himself to two fours, Gayle did what he is best at -- hitting Jeevan Mendis straight over his head for a six to get the local crowd on their feet.
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That was just the beginning of Gayle's assault as he hoicked Nuwan Kulasekara over deep midwicket for another maximum. The next ball was carted over wide long-off for same result.
Sri Lanka's pace spearhead Lasith Malinga was not spared either as his fast bouncer flew off a top-edge for six.
Gayle got to his century with a cheeky single to mid-off, got down on his knees, arms aloft, to celebrate yet another awe-inspiring knock.
Even as Gayle was making a mockery of the chase, the others looked intent on making a heavy weather of it.
While Kieorn Pollard was unlucky to have been wrongly given out lbw by fellow Jamaican Joel Wilson, Darren Bravo's run out seemed unnecessary.
Earlier, West Indies rode on Sunil Narine's 4/40 to bowl out Sri Lanka for a modest total despite skipper Angelo Mathews' battling, unbeaten half-century.