The All Blacks have seemed almost unbeatable over the past few years as they charged to the world number one ranking.
And Mortlock insists Graham Henry's side remain favourites for the showpiece tournament in the autumn in France.
"The All Blacks have been ranked number one through their consistency and their ability to play well both home and away," Mortlock said.
"From our end we targeted this match as a very important match and one we were hoping to win, and I still don't think that changes the mindset that the All Blacks are the team to beat."
The Wallabies outside-centre produced a man-of-the-match performance to spark a second-half revival with the hosts trailing 15-6 at half-time in the Bledisloe Cup clash in front of 79,000 fans at the Melbourne Cricket Ground.
All Blacks prop Tony Woodcock and winger Rico Gear crossed for tries in the third and 26th minutes as the visitors dominated the opening period.
But after Daniel Carter's conversion, the Kiwis failed to score another point in the match, while the Wallabies ran in converted tries through wing Adam Ashley-Cooper and reserve centre Scott Staniforth to steal an historic five-point victory.
"We spoke about that at half-time and spoke about shoring up our defensive line, and we were very happy with the way the team - the forwards in particular - played defensively out there," said Mortlock.
"There were a couple of times in the first half where the pace was quite frenetic and I think everyone was hurting.
"And there were a couple of times in the second half when we got the momentum to swing our way although they were attacking us still, but that's what you expect in Test matches - it's a test physically and mentally, and there were times when both teams were tested."
Mortlock, who was concussed midway through the second period in a rolling tackle on Gear, agreed the turning point in the match came when All Blacks prop All Blacks prop Carl Hayman was sin-binned in the 62nd minute, allowing the Wallabies to take the lead with two tries.
"I guess that was the result of the forwards giving us quality possession," said Mortlock.
"We scored when they had a man in the bin and I'm pleased we took advantage."