Fremantle forward Hayden Ballantyne has dismissed suggestions the Freo Dockers have deliberately taken their foot off the pedal in the second half of games this season.

Freo is two games clear at the top of the AFL ladder after six straight wins to start the season.

But despite producing some comprehensive wins, some attention has been drawn to their second-half performances.

In round three, Fremantle led West Coast by 66 points at half-time before winning by only 30. In round four they led the Sydney Swans by 48 points at half-time and won by 14.

Last Saturday night, Freo led Essendon by 54 points at three-quarter time before the Bombers kicked four goals to none in the last quarter to trim the final margin to 28.

However, in round five, Fremantle dominated the last quarter against Melbourne, extending their three-quarter time lead of five goals to a final margin of 68 points.

After Saturday's win over the Dons, Freo coach Ross Lyon explained he managed some of his defenders in the last quarter, which affected their structure.

Fourth quarter 'fade out' explained

On Tuesday, Ballantyne said it would be a dangerous ploy if Fremantle deliberately let sides back into games.

"If you practice letting clubs back in, that's not going to be a great thing for us if we do eventually play finals," Ballantyne said.

"It's not something that we practice, to have a fadeout, that's for sure.

"We were changing a few things around on the field (against Essendon). Michael Johnson had really high minutes in the first two or three quarters, so he had a bit of a rest in the last quarter.

"It's definitely not a tactical thing to fade out in games. But it is something… that we have to work on. We can't just let teams kick quick easy goals in the last quarter."

Freo's defensive pressure has been manic across the first six rounds. Ballantyne conceded fatigue did set in later in games due to maintaining such a high intensity of pressure during the first half.

Ballas backed by team

"I suppose fatigue comes into it a little bit, but at the same time the opposition is just as fatigued too," Ballantyne said.

"That's our trademark in the forward line, to chase, harass, pressure and then the goals come after that. So we do our best to do it for the whole game.

"Obviously there is going to be lapses. There's going to be fatigue coming into it as well. But we do our best to have four quarters of absolute pressure and hopefully that will get better and better as the season goes by."

Ballantyne said Freo's pressure would have to be first-rate this Sunday when they face a Western Bulldogs side hungry to atone for last week's loss to St Kilda.

"The Bulldogs have been playing some great footy this year," Ballantyne said.

"I actually like watching (Marcus) Bontempelli play. He's a gun.

"We have to show them full respect because they can tear a game apart really quickly."