The Brisbane Lions captain is not one for exaggeration but did not sidestep the display that saw his team trail by 72 points at half time before eventually losing by 65.
Brown said the Lions had been taught a lesson and the only positive was they did not have to wait long to learn from it with Sunday's match against Carlton at Etihad Stadium.
"We certainly won't lack motivation this week I wouldn't have thought," he said.
"We've got to look forward to the challenge of playing a top four team. We probably haven't come up against a top four team yet so we've just got to prepare and come back with a better attitude."
But it will take an enormous reversal in form as the Lions were completely smashed in the first-half by the Swans.
Sydney won the disposal count 110-52 in the first quarter and 207-121 for the half, and dominated clearances 14-2 in the opening term.
"It was terrible, the first half was just terrible. Our heads obviously weren't in it in the first half so it's a big kick up the backside for us and we got taught a lesson by a very good team," Brown said.
"No excuses, we didn't come prepared. What we served up in the first half was just unacceptable.
"It was a really poor effort by us. Not often you come in at half-time and you're 70 points down, especially on your home paddock."
Brown said the Lions contested possessions simply had to improve, and it was no surprise the one time the Lions had mastered that area this season they came away with a 40-pointwin against Adelaide on the road in round 10.
He said the Lions were reactive and flat-footed and needed to improve.
The big forward had limited opportunities of his own, with the ball going inside the Lions' forward 50 on just two occasions in the first quarter, and primary opponent Heath Grundy being helped by Ted Richards most times it came forward throughout the match.
Brown continued to give a strong contest and grabbed five contested marks for the night.
"Out of the 22 it was a poor effort by all of us," he said. "They really test you one-on-one and we didn't cope with it at all which is disappointing because we want that to be a strength of our game."
