On a day when he became just the third Swan in the club's 110-year history to reach 250 AFL games, O'Loughlin kicked two vital goals in the final term to spark Sydney to a 13.18 (96) to 10.9 (69) triumph over the previously undefeated Lions.
O'Loughlin finished with three goals, while Barry Hall made a mockery of his fitness cloud to kick four as the Swans piled on 5.8 in the final term to Brisbane's solitary point to move to 2-1 for the season.
Hall's efforts took him past 500 goals for his career, while Swans ruckman Darren Jolly played his 100th game and Jonathan Brown kicked his 200th goal for Brisbane on a day littered with milestones.
But O'Loughlin was the main focus for the Swans and a stirring address from co-captain Brett Kirk at three quarter-time, who demanded Sydney lift to give the man known as 'Magic' a day he deserved, ignited the previously lethargic home side.
The Swans led by a goal at the first change but the fleet-footed young Lions, who topped the ladder heading into round three, purred beautifully in the second and third quarters to appear on track for an upset win.
But the Swans, traditionally slow starters, found their groove in a commanding final term.
"It was good to get away in the end with the win, but we made hard work of it for three quarters," Sydney Swans coach Paul Roos said.
"I think the positive thing is we're not playing great footy but we're 2-1. Last few years we haven't played great footy and been 0-2, 1-2, that sort of thing.
"To have 13 scoring shots to one in the last quarter against a young, fit team with plenty of confidence is a massive positive."
Hall, who has become one of the most feared and respected figures in the game after a checkered beginning at St Kilda, kicked his 500th AFL goal in trademark style.
Using brute strength to rid himself of opponent Daniel Merrett, Hall coolly slotted home from 40m out for his third for the game.
Hall showed no signs of the knee and ankle injuries he sustained in last week's victory over Richmond.
Roos said his side's start to the season indicates their fitness is a major benefit.
"Leading into the season I thought we'd be fit again this year and we definitely are," he said.
"We're a lot fitter and that showed today. We came back against West Coast and gave ourselves a chance to win, won last week in the last quarter and today again.
"Now we've just got to work on some other aspects, including our skills."
SYDNEY 5.3 7.6 8.10 13.18 (96)
BRISBANE 4.3 7.4 10.8 10.9 (69)
Goals: Sydney: B Hall 4 M O'Loughlin 3 T Schmidt 2 A Schneider B Mathews R O'Keefe L Barry. Brisbane: J Brown 3 A McGrath 3 J Patfull C Begley B Fixter S Harding.
Best: Sydney: B Hall D Jolly N Fosdike M O'Loughlin R O'Keefe C Bolton T Schmidt. Brisbane: A McGrath J Brown L Power S Black B Fixter.
Umpires: B Allen C Kamolins S Meredith.
Official crowd: 24,854 at the SCG.
