Fremantle kicked nine goals in a rampaging final quarter to beat Sydney by 38 points at Optus Stadium on Thursday night, 15.21 (111) to 10.13 (73), after trailing the second-placed Swans at every change.

The Dockers did not kick a goal before half time. Their 0.11 (11) at the main break, against Sydney's 4.9 (33), was just the third goalless first half in the club's VFL/AFL history, and it came in front of 55,966 people, which the AFL reported as Fremantle's biggest home crowd outside a derby. The annual Starlight Purple Haze game had the house; for two quarters it did not have a home goal.

The second half was a different match. Fremantle piled on 15.10 (100) to 6.4 (40) after the break, won the second-half clearances 25 to 15 and the inside-50s 40 to 22, and turned a two-point deficit at the last change into a 43-point lead in about 14 minutes of the final term. Playing on a five-day break, a week after GWS ended their 14-game winning run, the Dockers have now won 15 of their past 16.

Josh Treacy kicked four goals, with Shai Bolton, Michael Frederick, Pat Voss and Jye Amiss adding two each. Murphy Reid and Caleb Serong had 28 disposals apiece, Serong with seven clearances, and Alex Pearce anchored the defence in one of his better nights of the season. Mason Cox, recalled for his first game since round 15, drew praise from coach Justin Longmuir: "I thought it was the best he's marked the footy, and I thought his ruck work was strong."

Longmuir was not surprised the scoreboard eventually obeyed the territory count. "Law of averages will say that you're not going to kick 0.22 for the game," he said. For Sydney, Charlie Curnow kicked five goals from 14 disposals and Errol Gulden led the ground with 30 touches, but coach Dean Cox saw the same pattern that has followed his side all year. "At the minute, we sit second on the ladder, but some of the football we're playing at times, we need to be better at," he said. "It shows you can do it; you just can't do it for long enough."

The AFL's taunting rule made two appearances, with free kicks paid against Fremantle's Luke Ryan and Sydney's Dane Rampe. Longmuir kept his complaint short: "It's clear. The AFL said it's clear. Maybe we could have educated our players a little bit better."

Fremantle sit on top at 15-2, two games clear, though the rest of round 18 gives the chasing pack a game in hand. The Dockers travel to Adelaide Oval to face Port Adelaide next Saturday, while Sydney, second at 13-4, host Adelaide at the SCG on Friday night in round 19.