AAP


The Sydney Sixers can lay claim to being the best Twenty20 side in the world, but skipper Brad Haddin is confident complacency won't be an issue for the reigning Big Bash League champions this season.


A blistering knock from Haddin on Saturday night ensured the Sixers started their BBL title defence with a 12th straight T20 win, a seven-wicket triumph over cross-town rivals the Thunder.


It was a reasonably clinical performance, suggesting the team have lost little since landing the Champions League title in South Africa in October.


Rather than rest on their laurels after a $US2.5 million ($A2.40 million) payday in Johannesburg, Haddin said his teammates have been hard at work to ensure they're still a T20 force.


"I think Twenty20's a hard game to get on top of," Haddin said after his match-winning innings of 59.


"You've got to keep challenging your side to get better and better, and I don't have to do that because they're challenging each other to get better.


"I've been very happy with the progress of this team, what I like most about them is that they keep challenging themselves at training to get better.


"I haven't had to say anything to get them up.


"It's a lot more fun when you're winning cricket games."


The 35-year-old wicketkeeper, who has previously conceded he holds little hope of a Test recall, didn't want to talk about his own fine form after the comfortable victory over the Thunder.


"I'm pretty content with where things are at," Haddin said before deflecting all the batting plaudits to Nic Maddinson (39) and Steve Smith (41no).


The Sixers are next in action on Sunday, when they host Perth Scorchers in a BBL grand-final rematch at the SCG.