A PULSATING round-four clash at the MCG has ended with Port Adelaide upsetting Hawthorn by 30 points.

The Hawks' 17.13 (115) to 12.13 (85) loss was further soured by a hamstring injury to Brent Guerra who left the field in the second quarter and did not return.

The match was set for a grandstand finish after scores were tied at three-quarter time but the Power ran away with the victory to give them a 3-1 start to the season.

The deadlock was broken early in the fourth quarter with a goal to Robbie Grey, but it was the next major score that proved to be the gamebreaker.

After absorbing plenty of pressure in defence, the Hawks broke free and carried the ball down field where Lance Franklin marked at close range.

Inexplicably, the Coleman medallist played-on. He was brought down and the Power swept the football all the way to the other end where Dean Brogan put the visitors two goals in front.

Sam Mitchell, who battled injury and the excellent Kane Cornes on a quiet afternoon by his standards, gave the Hawks life with a mark and goal, but Tredrea's sixth and Brendon Lade's second put the issue beyond doubt.

Hawthorn began slowly on a day when most of its stars were well held.

Mitchell and Luke Hodge were tireless, but below their usual output, and Jarryd Roughead was shut out of the game by Power defender Troy Chaplin.

Franklin contributed well with three goals and Cyril Rioli was his usual mercurial self in collecting 23 creative disposals.

Young gun Garry Moss continued the impressive start to his AFL career with a goal and 25 touches, but the Hawks simply did not have enough winners on the day.

After finding itself down by three goals midway through the first term, Hawthorn shrugged off their lethargy to strike back chiefly through Franklin, who goaled on either side of the quarter-time siren to bring his team back into the contest.

A goal to Stuart Dew seemed to deliver momentum to the Hawks but the Power would not lie down. Tredrea matched Franklin's influence at the other end of the ground and Grey's first goal gave the visitors a slender lead at half time.

A wasteful third-quarter saw the Hawks kick 4.6 to Port Adelaide's 4.2 and spurn the chance to take a lead into the final term.

It was inaccurate finishing the premiers would come to rue as they fell to their third loss for the season.

The 1-3 record has Hawthorn’s flag defence off to a shaky start, especially considering its mounting injury toll.

Next week, the Hawks take on West Coast at Aurora Stadium in Tasmania.

Hawthorn  2.2  5.6  9.10  12.13 (85)
Port Adelaide  4.3  6.4  10.6  17.13 (115)

GOALS
Hawthorn: Franklin3, Rioli 3, Sewell, Campbell, Dew, Moss, Mitchell, Hodge
Port Adelaide: Tredrea 6, Ebert 2, Logan 2, Lade 2, Gray 2, Rodan, Pearce, Brogan

BEST
Hawthorn: Sewell, Bateman, Rioli, Young, Morton, Franklin, Williams,
Port Adelaide: K.Cornes, Tredrea, Chaplin, Salopek, Boak, Carlile, C Cornes, Logan

INJURIES
Hawthorn: Brent Guerra (hamstring), Travis Tuck (shoulder) replace in selected side by Beau Dowler.
Port Adelaide: Shaun Burgoyne (bruised knee) replaced in selected side by David Rodan.

Reports: Nil
Umpires: Vozzo, Nicholls, Armstrong
Official crowd:  33,274 at MCG

The views in this story are those of the author and not necessarily those of the clubs or the AFL.