This story originally appeared on afl.com.au

COLLINGWOOD has kept its top-four bid alive and left Port Adelaide's finals hopes hanging by a thread after a rampaging seven-goal final quarter set up an emphatic 51-point victory at the MCG on Saturday.

The Magpies led by just six points in the dying minutes of the third quarter after the teams had waged the type of hard-fought contest you'd expect of clubs looking to position themselves for successful September campaigns.

However, the game turned decisively when Steven Motlop conceded an undisciplined 50m penalty late in the third term.

It sparked a run of eight unanswered Collingwood goals and, with the Power not adding another major until the dying seconds of the game, the Magpies cruised to a 17.13 (115) to 10.4 (64) victory that broke a four-game losing streak against Port.

Collingwood, who started the round fifth on the ladder less than three per cent behind fourth-placed Hawthorn, climbed to third after their win, but will likely slip back to fifth by the end of Saturday if Greater Western Sydney beats Sydney at Spotless Stadium and the Hawks defeat St Kilda at Etihad Stadium.

There had been heavy rain in the lead-up to the game, but the sun came out in time for the opening bounce and kept shining for much of the afternoon.

Magpies fans were smiling just as brightly at the end of the game as they looked forward to their first final series since 2012.

Collingwood led by one point at quarter-time and 17 points at half-time, but knowing their season was on the line the Power responded, closing to within four points after kicking the opening two goals of the third term, through Robbie Gray and Paddy Ryder.

The game then descended into a defensive scrap – it had rained briefly at the start of the third quarter – as both teams struggled to find a decisive way forward, with backwards handballs, hurried kicks and turnovers the order of the term.

The Power let the Magpies off the hook late in the quarter, however, when Motlop gave away the fateful 50m penalty after hitting Brayden Maynard in the chest.

It was not forceful enough to warrant a report, but it was enough to put Adam Oxley within scoring distance and the Magpie defender made no mistake with his set shot to give Collingwood a 12-point advantage.

Brodie Grundy (25 possessions, 41 hit-outs, eight clearances and eight tackles) was outstanding in the ruck for the Magpies, as were Taylor Adams (30 possessions – 23 in the first half – seven tackles and five clearances), Steele Sidebottom (33 possessions, five tackles and one goal) and Scott Pendlebury (25 possessions, seven tackles and five clearances) through the midfield.

Brayden Maynard (23 possessions and eight tackles) mixed stingy defence with damaging counter-attack, while Chris Mayne (27 possessions) continued his resurgence this year.

Port's loss was its third in a row and its fifth from its past six matches.

After round 16 the Power had sat fourth on the ladder, but to make the finals they will now have to defeat Essendon at Adelaide Oval next Friday night and hope other results fall their way.

Port captain Travis Boak (27 possessions, five clearances and two goals) led from the front, and received able support through the midfield from Motlop (28 possessions and five clearances) and Ollie Wines (29 possessions and four clearances).

Mobile tall Justin Westhoff (22 possessions, 10 tackles and one goal) worked hard all over the ground, while Paddy Ryder (three goals) was noticeably restricted by his hip and Achilles tendon issues but at least gave the Power a target in attack.

COLLINGWOOD          4.2       9.7       10.11    17.13 (115)
PORT ADELAIDE         4.1       7.2       9.4       10.4    (64)

GOALS
Collingwood:
 Stephenson 2, Phillips 2, Mihocek 2, De Goey 2, Sier, Varcoe, Adams, Oxley, Sidebottom, Cox, Grundy, Mayne, Thomas
Port Adelaide: Ryder 3, Boak 2, Westhoff, Watts, Polec, R.Gray, S.Gray

BEST 
Collingwood: Adams, Grundy, Pendlebury, Sidebottom, Mayne, Maynard
Port Adelaide: Motlop, Boak, Westhoff, Wines, Polec, R.Gray

INJURIES 
Collingwood: De Goey (leg)
Port Adelaide: Watts (left knee)

Reports: Nil

Umpires: Dalgleish, Nicholls, Fleer 

Official crowd: 46,286 at the MCG