The New Zealand club dropped to eighth on the table after the 2-1 loss to Perth Glory on Sunday but they plan to halt that slide when the Sky Blues come to town on Saturday evening.
Phoenix coach Ricki Herbert said the performance against the Glory wasn't so and indicated that with better concentration, a win against the bottom-placed Sydney side was very achievable.
"We probably had a lot more of the ball today than we've ever had in Perth," said Herbert after the loss.
"We had some chances but we coughed up a couple of silly mistakes and were not tight enough in a couple of areas."
Wellington host Sydney at Westpac Stadium, where they are unbeaten in 21 matches, on Saturday - kick-off is at 7:15pm local time (5:15pm AEST).