South Australia 240 (Nielsen 90, Bartlett 4-64) and 3 for 246 (McSweeney 77*, Lehmann 68*, Carder 54) drew with Queensland 342 (Burns 85, Clayton 67, Bazley 64*, McAndrew 5-93)
On a fighting final day in Adelaide, the pair batted through 65 overs to help wipe out Queensland's 102-run first innings lead and take South Australia to 3 for 246 when the match was called.
Wednesday's result leaves the Bulls still in second spot on the ladder, but vulnerable of falling below Tasmania at the halfway point of the season if they beat Victoria this week.
Under Sheffield Shield rules the top two teams qualify for the March final, with the majority of the rest of the season to be played without Test stars.
After the hosts fought back to be all out for 240, the Bulls then had the chance to build a big first-innings lead of close to 200 and push for an outright result at 2 for 184 in reply.
But when Joe Burns ran himself out on 85, Queensland lost eight wickets in the middle session of day three to be all out for 342 and a lead of 102.
Queensland then had one last sniff when Bartlet had Daniel Drew (37) edging on the first ball of the fourth morning, with his second-innings figures of 2 for 48 to go with his first-innings 4 for 64.
The right-armer also then swung one across Jake Carder (54) to have him caught at third slip, leaving the Redbacks three down while still trailing by two.
But then came McSweeney and Lehmann, with the former soaking up 218 balls for his unbeaten 77 and the latter scoring 68 from 181.
The pair batted smartly in their 146-run stand, with the only major opportunity coming when McSweeney survived a close run-out call just before lunch.
At one stage quick Gurinder Sandhu even turned to off spin, while Burns and fellow opening bat Bryce Street were both also used with the ball.
The result means South Australia momentarily go ahead of NSW who are now bottom of the ladder, pending the result of the Blues' clash with Western Australia at the SCG.