Gilchrist and Waugh put on 151 for the first wicket and Gilchrist and Ricky Ponting put on 74 runs for the second.
When the Lankans made 259 for 9 it looked a big task for the Australians. But after playing down two maiden overs, Gilchrist and Waugh were quickly into their stride and once they got their act going, they took the Sri Lankan attack by the scruff of its neck and smashed it to all parts of the field and over it with consummate ease.
Waugh went for 63 with 3 fours made in 76 balls and when the Gilchrist batting massacre ended the Aussies were well on the way to an easy win. Gilchrist was out at 225.
When victory was achieved Ponting was on 43 and Martyn on 16 and Australia had made their highest ever winning score at the SCG.
While the Sri Lankan batting obliged scoring 259, the bowlers and fielders lacked commitment and they allowed the Aussies to post an easy victory.
If the Sri Lankans are not going to make it their business to lift their game and be a more competitive side, it will be sad to see the world champions just making up the numbers.
Arjuna Ranatunga called correctly once again and gave his side first lease of a fine batting strip in which 'black superman' Sanath Jayasuriya and 'mauler' Romesh Kaluwitharne revelled to rocket Sri Lanka to their best start of the series.
They put on 95. But the Aussie openers posted a massive opening stand of 151 to make the Lankan opening stand the second best.
Sri Lanka left out Nuwan Zoysa and gave Mahela Jayawardena a go. Australia brought in left arm spinner Brad Hodge and dropped Adam Dale.
Jayasuriya and Kaluwitharne were soon off the start line and got quickly on the super highway of run making with Jayasuriya in the driving seat and in top gear.
Jayasuriya was the master as he blasted the ball to all parts of the field, while Kaluwitharne who is usually aggressive continued to support the dashing left-hander with nudges for singles. McGrath and Fleming could not get Jayasuriya to apply the brakes, and in his tearaway knock he was very severe on Greg Blewett clobbering him for 23 runs in two overs.
Jayasuriya got his beefy square cutting going and what a treat it was to see him going over the top as he was known to do. What a treat he provided with his natural approach. He was looking set for a big score when he went caught behind to a ball that moved. This is the third time that he has been out in similar fashion. His 65 came in just 62 balls and it was studded with 9 fours.
Kaluwitharne went at 106 for a patient 32 with 5 fours. He allowed Jayasuriya to dominate while he was content in playing second fiddle.
Marvan Atapattu went lobbing a catch to Mark Waugh at short mid off for 18. Hashan Tillekeratne and Ranatunga got together to add 53 useful runs for the fourth wicket before Ranatunga who was slowly regaining his lost form was run out for 26. The third umpire took long to rule him out. Tillekeratne accustomed himself well batting in Aravinda de Silva's spot, though he is not as explosive as de Silva. He made his third half century of the tour making 73 in 95 balls with 3 fours. Jayawardene, Chandana and Mahanama went cheaply and Sri Lanka posted a good score of 259 for 9 in 50 overs.
'Captain Cool' was not disappointed with the result. He admitted that the loss of Aravinda de Silva was a big blow but promised to come back and he concerned at the finish.
The Lankans now move on to Sydney and clash with Australia on Wednesday.
The Sri Lankans when they batted were off to a shock start when left hander Sanath Jayasuriya was out to the second ball he faced in the first over of Darren Gough with the score only on 2 after pushing a single in the first ball. England were delighted to see the back of Jayasuriya who thrashed them for a double hundred in the Test match at the Fostor's Oval. Jayasuriya showed his weakness again to a delivery pitched outside off stump and moving away to give Grame Hick a slip catch.
Marvan Atapattu who had not been in good form on this tour, joined the man in form Romesh Kaluwitharne and together they produced the best batting of the innings.
They were not overawed by the early loss of Jayasuriya. They settled down to some effective batting and dished out a batting treat that was lapped up by the crowd especially the slossies (that's how the Lankans domiciled here are known).