In the last of the quarterfinals, Barty and Dellacqua briefly looked liked springing an upset before the French turned the match on its head to run out 1-6, 6-2, 6-1 winners.
Barty and Dellacqua were finalists at their home major four years ago and, as they had against Martina Hingis and CoCo Vandeweghe the previous round, lit up the Rod Laver Arena with some sparkling tennis early on.
However, the favorites began to turn the tide midway through the second set, producing two clean winners to break Barty's serve for a 4-2 lead. From this point on it was one-way traffic, Garcia and Mladenovic easing into a maiden Melbourne park semifinal, where they will face No.12 seeds Andrea Hlavackova and Peng Shuai.
Garcia and Mladenovic could reach the top of the rankings by reaching the final, but they will have their work cut out against Hlavackova and Peng, impressive 7-5, 7-6(5) winners over No.3 seeds Ekaterina Makarova and Elena Vesnina.
On the other side of the draw reigning World No.1 Bethanie Mattek-Sands and her partner Lucie Safarova laid down a marker by swatting aside No.11 seeds Raquel Atawo and Xu Yifan, 6-1, 6-1, in under an hour. Their reward is a meeting with the draw's surprise package, Eri Hozumi and Miyu Kato, after they overcame Mirjana Lucic-Baroni and Andrea Petkovic, 6-3, 6-3.