Just six days after we thought Geelong was near infallible, Port Adelaide demonstrated it was a genuine contender with a remarkable victory at Adelaide Oval on Sunday night, ending a painful 10-game losing streak to the Cats and replacing them at the top of the premiership ladder.

Buoyed by their courageous win over Hawthorn the previous round, and previously unbeaten this season, the Cats were stunned by Port's maturity and tenacity.

Everyone knew Port would go in hard, and it was a good side, but to respond to hard play and class from a hardened finalist was clearly the best indication Port was a worthy top-four side.

To hold Geelong goalless in the second quarter, after the lead changed seven times, took real character. To sustain the pressure the Cats applied took unrelenting resilience and composure.

The manner in which both sides played an attacking game was emphasised by there being only one backward kick in the first half - by Geelong's George Burbury on the wing at the 16-minute mark of the second quarter.

No one should start doubting Geelong - it was just surprising that Port was able to match it in such a determined manner. The Cats may not have been quite as sharp as the previous week, but then Port was also coming off a hard-fought win against West Coast in Perth.

In a contest where opportunities were hard to come by, Geelong must rue the opening of the first two quarters when it dominated play inside 50, yet kicked 0.3 both times. Missed were chances to stamp its authority, allowing Port to simply grind away.

As the occasion demanded, the game needed leaders, and Port was admirably served by former captain Dom Cassisi, new co-captains Brad Ebert and Travis Boak, and Kane Cornes. Add the next level of experience with quality performers such as Robbie Gray and Hamish Hartlett, and a list of star youngsters, and Port's team effort was complete.

There were occasions early when Tom Hawkins looked as if he would take this game apart, leaving Alipate Carlile in his wake. He was able to brush him aside too easily. However, Port managed to tighten ranks and cut off the supply chain.

Geelong had numerous other early key performers like Steve Johnson, the inexperienced George Horlin-Smith, and James Kelly, but as much as it seemed to be in control, there were too many times Port seemed to surprise by showing that touch more ferocity for the ball.

When Port led by 18 points at half-time it was expected that Geelong would rebound in grand style. When Port kicked the opening three goals within six minutes of the third term there was the realisation that Port was up there with the best, and as the match wore on Port grew in confidence.

Joel Selwood was under close attention. For the most part, under difficult circumstances for Selwood, Cornes had his measure.

Geelong kicked its fourth goal seconds before the quarter-time siren - few could hear it - and its fifth from Mark Blicavs 16 minutes into the third quarter. In between Port kicked 7.2 to 0.6. It was a telling factor in the context of this match, especially when the Cats kicked their sixth two minutes later to get within four goals. Again, Port withstood the pressure, but not without enormous concern.

It was a tough contest, and it got tougher in the third quarter, with Jimmy Bartel and Aaron Young banging heads. Moments later, a 50-metre penalty to the Power led to Sam Gray kicking a goal off the ground less than a metre out, and then Harry Taylor missing a ''sitter''. . It told us Geelong was not quite on song.