Goals from Josh Nisbet and Mikael Doka moved the Mariners a step closer to the grand final on Friday, as Jackson's side seek the chance to complete a treble.
Should they advance to the grand final with an aggregate win in Gosford next Saturday, Jackson's side would have the chance to defend their title on home soil.
The Mariners have previously been made to move grand finals to larger stadia in Sydney but the club have successfully lobbied to host a potential decider at their Industree Group Stadium.
But Jackson is refusing to let his side get too far ahead of themselves, arguing Sydney have the ability to rescue a result from the tie.
"We're delighted that the club has worked hard to get that fixture but we're not there yet," Jackson said.
"We're not there, we're far from it.
"Sydney are a formidable team and they're a dangerous team.
Jack Rodwell, here getting a yellow card, ended up seeing red for Sydney. (Dean Lewins/AAP PHOTOS)
"People say beware of the wounded animal and we've got to be prepared for what they're going to bring.
"We'll do our homework, we'll prepare the place physically and we'll be ready but we expect a tough battle."
Jackson was ecstatic with how his side stood up to Sydney, who had beaten the Mariners twice throughout the regular season.
But the Sky Blues were reduced to nine men after Jack Rodwell (63rd minute) and Corey Hollman (82nd minute) were sent off in Friday's game and they struggled to create, their sole shot on target through the 90 minutes being Joel King's goal.
"We showed courage to play through their press," Jackson said.
"I felt maybe their goal went against the run of play, that might be a bit harsh saying that, but I felt that at the time.
"We didn't wobble under the pressure and then we got back into the game.
"It's two good teams, two competitive teams going at it toe-to-toe, and those are the kind of games we like."
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