Jay Schulz booted seven goals for the Power as the home team destroyed its hapless opponent, 24.15 (159) to 7.4 (46).
Adding to the Lions' woes was the loss of star midfielder Pearce Hanley.
Leuenberger will have scans on his right knee and Hanley strained a hamstring.
The Lions had no clear winner apart from Tom Rockliff (31 disposals, 14 tackles) and Rohan Bewick, who kicked two goals.
The Lions kept pace in the first term and trailed by eight points at quarter-time in a heartening opening.
But they were then blown away as Port booted 14 goals to two in the second and third quarters.
The Lions' cause was hampered by the loss of tap-man Leuenberger, who hobbled from the ground in the second term after injuring his right knee in a tangle with opponent Matthew Lobbe.
Lions officials believe Leuenberger avoided damage to his anterior cruciate ligament, with scans to determine the exact nature of his injury.
Hanley limped off in the third quarter with a hamstring strain and also appears certain to miss games.
PORT ADELAIDE 4.4 10.9 18.13 24.15 (159)?
BRISBANE LIONS 3.2 4.3 5.3 7.4 (46)
GOALS?
Port Adelaide: Schulz 7, White, Westhoff, Sam Gray 3, Robbie Gray 2, Wines, Polec, Boak, Impey, Young, Ebert
Brisbane Lions: Bewick 2,Mayes,Brown, Clarke, Redden, Zorko
BEST
Port Adelaide: Boak, Ebert, White, Cornes, Cassisi, Schulz?
Brisbane Lions: Rockliff, Redden, Moloney, Mayes, Zorko,Adcock
INJURIES
Port Adelaide: Nil?
Brisbane Lions: Leuenberger (knee), Hanley (leg)
SUBSTITUTES?
Port Adelaide: Jack Hombsch replaced by Aaron Young at three quarter-time?
Brisbane Lions: Matthew Leuenberger replaced by Tom Cutler in the second quarter??Reports: Nil??Umpires: Donlon, Hay, McInerney??
Official crowd: 36,231 at Adelaide Oval
