Tipped by many pundits to struggle that season after the retirement of stars Paul Kelly, Andrew Dunkley and Wayne Schwass, the Swans defied expectation in Paul Roos' first year as senior coach to host a preliminary final at ANZ Stadium.
Now, Kennelly says the new-look Swans are set to surprise the football world again.
"There's great excitement amongst the team and it really has the feeling of 2003," he said.
"We're very unpredictable and we're quietly confident amongst ourselves. The whole AFL world are putting us down, which is great. The Swans love being underdogs."
Kennelly, 28, said the Swans' off-season injection of running power was set to cause more than a few headaches for opposition teams, with the likes of Ben McGlynn, Lewis Jetta and Gary Rohan providing some badly needed pace.
"You try and match the inside players like Jude Bolton and Brett Kirk, but then you've got to match the outside players as well. You've got to have speed outside to mark them," he said.
"But I think the biggest benefit, as I said, is that other teams aren't rating us. I'm sure we'll get under the guard of a lot of teams."
In many ways, Kennelly's 2010 pre-season has mirrored that of the whole club.
The Irishman has returned to the AFL both mentally and physically refreshed after winning an All-Ireland Gaelic football title with his county Kerry in 2009.
His last years with the Swans were hampered by injury and Kennelly said the prospect of returning to his best was his main motivation for coming back to Australia.
"I wasn't happy with the way I finished here in '07 and '08. I had injuries and I wasn't able to play the way I wanted to play," he said.
"Now I've been a year out of the game, I've finished at home doing something I always wanted to do and I thought, 'You know what? I want another challenge.'
"Let's see if I can go back to Australia and get to the level I want to as a footballer again."
Swans coach Paul Roos said Kennelly's strong pre-season form indicated he could potentially be one of the season's best recruits.
"He's a terrific player, a really important player for us, but I think Tadhg will be the first to admit that we're not just relying on him to get back up the ladder," he said.
"It's got to be across the board improvement, but certainly having Tadhg back is more important after losing Hally and Mick and Leo and Crouchy because he's just terrific off the field.
"He's a great leader who leads by example and then obviously his footy stuff's pretty good too."
The Sydney Swans clash with St Kilda this Saturday night under lights at ANZ Stadium. Our last two contests with the Saints have been decided by only one point, so this game is guaranteed to be a thriller! Grab your tickets now at www.ticketek.com.au
