The 2010 champions seized the initiative with a unanswered seven-goal scoring spree in the opening quarter and cleared out in the third period, outscoring their opponents 17-10.
To the Steel's credit, the visitors clawed back some of the deficit with an impressive finish, winning the final quarter 16-13.
Replacement shooter Te Paea Selby-Rickit made a positive impact with 10 goals from 13 attempts and Donna Wilkins top-scored for the Steel with 20 goals from 23 attempts.
Carla Borrego starred for the home side with 40 goals from 46 attempts and fellow shooter Erin Bell was deadly accurate with 18 goals from 19 attempts.
The Steel opened the scoring through Jodi Brown (18 from 25) but an early miss and a clumsy pass saw the Thunderbirds score the next five goals.
Some good defensive work in the midcourt helped the Steel trim the gap to a single goal.
Hayley Saunders showed good desperation and made some valuable deflections.
But Thunderbirds were too polished for the visitors, piling on seven unanswered goals to lead 14-9 at the break. It rather set the tone for the remainder of the game.
The Steel got bogged down trying to find a way around the Thunderbird defensive paring of Rebecca Bulley and Sharni Layton.
Layton, in particular, picked off a brace of intercepts. Down the other end the Steel defenders Demelza McCloud and Sheryl Scanlan laboured against their opponents.
Borrego dominated the aerial exchanges, using her 1.93m frame to gain a crucial advantage.
Steel co-coaches Natalie Avellino and Janine Southby reacted by dropping Scanlan to the bench for rookie defender Storm Purvis, and Shannon Francois replaced Courtney Tairi at wing attack.
The Thunderbirds outscored the Steel by five goals to one in the opening 5min of the second half to stretch the lead to 10 goals.
When the combined Otago-Southland team look back at the tape from the third quarter, it will make for disappointing viewing.
• In the earlier match, the top-of-the-table Melbourne Vixens extended their unbeaten run this season to six games, thrashing the struggling Canterbury Tactix 65-41 in Christchurch. The Tactix are anchored to the bottom of the table with just one win from six games.
ANZ Championship
The scores
Adelaide Thunderbirds 58
Carla Borrego 40 from 46, Erin Bell 18/19
Southern Steel 48
Donna Wilkins 20/23, Jodi Brown 18/25, Te Paea Selby-Rickit 10/13)Quarter 14-9, halftime 28-22, third quarter 45-32
