Sixers captain Steve Smith elected to field after winning the toss and it proved to be an inspired decision.The Thunder made 6-166 from their 20 overs, but the men in pink chased down their victory target for the loss of just four wickets and with 10 balls to spare as they ended up on 4-167.
The result means the ANZ Stadium outfit have lost their past 14 matches in the BBL and have failed to register a win since December 23, 2011.
Usman Khawaja (66 off 51 balls) and David Warner (50 off 31) laid a very good platform for the Thunder as they put on 116 runs for the first wicket.
But after Mark Cosgrove (1-10 off one over) had Warner caught by Jordan Silk, it went pear-shaped for the visitors who lost 6-50 after appearing set to compile a huge total.
Moises Henriques (2-24) was the pick of the Sixers' bowlers and crucially claimed the scalp of top-scorer Khawaja who was caught behind by Daniel Smith.
In reply, the Sixers, guided by man-of-the-match Nic Maddinson (61 off 40), never looked seriously threatened on their way to victory.
Maddinson clobbered six fours and four sixes while Henriques (28 not out off 18) and Ravi Bopara (27 not out off 17) guided the hosts home with an unbeaten 50-run fifth-wicket partnership.
Gurinder Sandhu was the Thunder's best bowler with 1-25 off four overs at an economy rate of 6.25.