Sania Mirza's aim for her seventh major tennis title ended in despair as she and Croatian partner Ivan Dodig were beaten 2-6, 4-6 by unseeded American Abigail Spears and Colombian Juan Sebastian Cabal in the Australian Open mixed doubles final here on Sunday.

The Indo-Croatian pair accepted defeat in one hour and three minutes.

Sania was bidding for her seventh major tennis title, and first with Croatian partner Ivan Dodig, in the Australian Open mixed doubles final where the second seeds took on the unseeded American-Colombian pair.

Sania and Dodig were pushed on the backfoot at the onset of the match, getting broken twice to trail 0-4. Dodig lost his serve in the opening game of the match after a forehand unforced error.

Sania too lost her first service game, third of the first set, unable to return a backhand shot.

The Indo-Croatian pair took a while to get going and began to combine well in the later stages of the first set, winning their next two service games. But it wasn't enough to save the set, surrendering it 2-6.

But they stepped up their energy in the second set. Beginning to play more as a team, they attacked Spears' serve in the second game after Dodig won the first service game.

The pressure they applied paid dividends as Abigail-Cabal was hit a backhand volley wide to trail 0-2. Sania then held on to her serve to go 3-0 up.

But Sania-Dodig couldn't maintain the momentum. Sania was broken in the seventh game with a backhand volley winner.

Abigail and Cabal held onto their serves to square the second set 4-4.

Dodig, yet to win a major title in mixed doubles, seemed nervous at the begging of the match owing to his relative inexperience in summit clashes.

And he failed to control his nerves at crucial stages of the match, losing his serve in the ninth game with a double fault to trail 4-5.

Spears served for the match in the 10th game and weren't subjected to much pressure, winning the championship with a forehand smash, which underlined their supremacy.

It was Sania's second Australian Open mixed doubles final after winning in 2009 with compatriot Mahesh Bhupathi.

Prior to Sunday's final, she won three mixed doubles titles, the last being the 2014 US Open with Brazilian Bruno Soares.

The 30-year-old Hyderabadi has six major titles in her kitty, three in mixed doubles and three in women's doubles.

The Indo-Croatian pair played their second Grand Slam final, having lost the French Open final to the experienced pair of Leander Paes and Martina Hingis last year.

Sania-Dodig overcame a tough one-hour-18-minute battle in the semi-final against Aussies Samantha Stosur and Sam Groth 6-4, 2-6, (10-5) on Friday.

Abigail and Cabal defeated Elina Svitolina of Ukraine and Aussie Chris Guiccione 7-6 (1), 6-2 in the last four stage.