An undermanned Sydney pulled off a thrilling comeback win over Carlton at Telstra Dome today to shore up their top four spot and dent the Blues' finals hopes.

The Swans were down by 28 points at several stages during the second quarter, but took over in the second half and then survived a late Blues rally to win 18.13 (121) to 18.11 (119).

The victory gave Sydney a six-point buffer in fourth spot, after fifth-placed Collingwood's loss to North Melbourne on Friday night.

But it was not without cost, with full-back Leo Barry and full-forward Michael O'Loughlin both going off injured in the third term and failing to return in the final quarter.

Carlton dominated the match until midway through the second quarter, but although they built a handy lead, some missed chances meant their control of the game was not fully reflected on the scoreboard.

The Swans lifted in the midfield late in the second term, with Jude Bolton playing superbly in the clinches to repeatedly drive his team forward.

And they made the most of their chances, with Henry Playfair and Ryan O'Keefe scoring from snaps, while clever centring kicks from Kieren Jack and Ted Richards set up Jarrad McVeigh for the last two goals of the half to cut the margin to 16 points.

It was all Sydney's way early in the third term as they kicked the first three goals to take the lead 10 minutes into the quarter.

Carlton star forward Brendan Fevola then had a purple patch at the other end, kicking two goals and setting up two others in the space of nine minutes, as Carlton surged again.

But the Swans responded with three of the last four goals of the quarter to be within five points at the last change.

Despite the loss of O'Loughlin and Barry, they carried their momentum into the final quarter, kicking the first three goals to build a handy buffer before withstanding the Blues' late charge.

O'Keefe, who ran hard all day from half-forward and also kicked three goals, was superb for the Swans with Bolton's performance also critical, while McVeigh's four-goal effort was important.

For the Blues, youngster Bryce Gibbs was outstanding, keeping Sydney superstar Adam Goodes to just three touches in the first three quarters, although Goodes eventually did have some impact with two second-half goals.

Fevola was also very good for Carlton with five goals and some strong tackling, while Andrew Walker contributed well in his first game for the year after a shoulder injury.

AAP