Australian duo Ash Barty and Casey Dellacqua lost in three sets to the Czech Republic's Andrea Hlavackova and Lucie Hradecka in the women's doubles final at the US Open.

Hlavackova and Hradecka, the tournament's fifth-seeded pair, lost the first set before triumphing 6-7 (4-7), 6-1, 6-4.

Meanwhile, Adelaide teenager Thanasi Kokkinakis advanced to the final of the junior boy's draw with a three-set victory in his semi-final.

Kokkinakis defeated Christian Garin of Chile 4-6, 6-3, 6-4.