McGrath struck 45 runs on Sunday and followed up with a career-best 6/37, combining with Amanda-Jade Wellington (3/29) to dismantle the Blues' batting line-up.
Caroline Ward complemented McGrath with a patient 27 and the Eagles reached a defendable score of 147.
Brooke Harris was a standout for Sturt, taking 3/24 and top-scoring for her side with 31, but the Blues were all out for 119 in reply.
Southern District pulled off a miraculous win over Northern Districts by defending a low-scoring innings.
The Stingrays struggled to get going with the bat, with only Sheridan Howell (15) and Donna Clark (11) cracking double figures.
Sophie Roberts (3/9) and First Grade debutante Emily Laird (3/22) both snagged three wickets for Northern Districts and the Stingrays were dismissed for just 81.
In reply, Tegan McPharlin (15) was best with the bat, but Hannah Sampson (4/14) and Kelly Armstrong (3/27) bowled stunning spells, removing the Jets' batting lineup for a miserly 61.