Since reaching the semi-finals at Wimbledon, Konta has won just two matches and the British number one failed to improve that stat as she failed to see off the big-hitting Barty.
The Australian stormed through the opening set, with three breaks of serve leading to a bagel, but Konta needed just one break of her own to take the contest into a decider.
Konta struck early in the third and had match points behind her own delivery at 5-4, but Barty recovered to eventually force a tie-break, which she dominated from start to finish.
After opening up a lead of 4-1, the 21-year-old did not look back and a 6-0 4-6 7-6 triumph was soon confirmed in two hours and 20 minutes.
Konta currently sits in the eighth and final place in the Race to Singapore but despite holding a sizeable advantage over the chasing pack, more wins will be required before the end of the season.