Charlie Curnow has starred with six goals as Carlton survived a huge fightback to strengthen their grip on an AFL top-four spot with a 15-point win over Sydney.

The Blues prevailed 15.12 (102) to 13.9 (87) at Docklands Stadium on Friday night in a contest between fourth and fifth on the ladder, sending a warning to the competition in the process.

Despite injured spearhead Harry McKay's absence, their brutal scoring power was on full show in a nine-goal second quarter that broke the game open.

But the Blues were forced to scrap as Sydney hit back, closing to within eight points late in the final term before Zac Fisher hacked through a steadying goal in time-on.

Swans co-captain Josh Kennedy will face scrutiny over a high spoiling attempt on Sam Docherty, during which he tore his right hamstring.

The clumsy effort split open Docherty's head, forcing the Blues defender off under the blood rule, and sparked a fierce melee as Carlton players rushed to remonstrate with Kennedy.

He was sat on the ground nursing his injured leg and was eventually helped off the field by two trainers as jeers from Blues fans rained down from the stands.

Curnow earned plaudits for a dazzling display in which he kicked five first-half goals and finished with the equal second-biggest haul of his 72-game career.

The Blues' midfield was dominant in the first half, leading their side to a 89-58 advantage in contested possession, which was 161-137 in their favour at full-time.

Sam Walsh (34 disposals), former Swans ball-winner George Hewett (32) and Patrick Cripps (19) were all influential, particularly before half-time, and Jacob Weitering was strong in defence opposed to Lance Franklin.

Luke Parker (26 disposals), Isaac Heeney (24) and Callum Mills (22) helped drag Sydney back into the contest.

Young tall Logan McDonald was a shining light in attack for the Swans, starting brightly and finishing with three goals, while Tom Papley also booted three majors for the visitors.

Carlton laid just four tackles in the opening term but there were signs of the impending avalanche as they dominated contested possession (42-23).

The home side cut Sydney's lead to one point with the final two goals of the first term, including one on the siren to Curnow.

And the dam wall burst as the Blues piled on the first five goals of the second quarter before taking a 38-point advantage to the main break.

Two Franklin goals helped spark Sydney during the third quarter as the midfield momentum shifted.

Big marks from Weitering, Tom De Koning and Lachie Plowman in the final term helped Carlton hold the Swans at bay.