MELBOURNE, Australia - Two-time US Open champions Bethanie Mattek-Sands and Jamie Murray delivered a dramatic first-round upset in the Australian Open mixed doubles competition, coming from a set down to defeat No.1 seeds Barbora Strycova and Marcelo Melo 3-6, 6-4, [10-7] in one hour and 32 minutes.

Controversy flared as early as the second game, when Mattek-Sands and Murray disputed a call of hindrance - an argument that stretched over 10 minutes and eventually involved both teams as the supervisor was called to court. The Anglo-American pair were ultimately awarded that point, which helped them build an early 2-0 lead - but a fired-up Strycova and Melo roared back to take six of the next seven games and a one set lead.

The Czech-Brazilian duo also threatened a comeback from a break down in the second set, with Strycova lofting a marvellous lob over Murray's head to break the Briton as he served for it - but with Melo then serving to level the score at 5-5, Murray was finally able to put away a smash on his team's fifth set point. The ensuing super-tiebreak found Mattek-Sands and Murray the sharper pair, with both delivering a series of excellent volleys to take the lead and eventually sealing the win as a Melo backhand sailed long.

In the second round, Mattek-Sands and Murray will face the intriguing first-time duo of 22-year-old Jelena Ostapenko and 46-year-old Leander Paes, who also survived a tiebreak shootout to overcome Marc Polmans and Storm Sanders 6-7(4), 6-3, [10-6] in a clash between wildcard teams. Ostapenko and Paes - who is playing his final year on the circuit - frequently produced scintillating tennis, with the Wimbledon mixed doubles finalist Ostapenko's no-holds-barred returning complementing 10-time mixed doubles major champion Paes's touch at net perfectly.

Ostapenko and Paes also displayed endearing chemistry, laughing their way through much of the match: a remarkable Ostapenko lob that sailed into the air and eventually came down on their opponents' baseline, with Polmans netting the ensuing smash, was one of many remarkable shots that caused them a good deal of mirth.

The Latvian-Indian pair could also be inconsistent, with errant Ostapenko volleys proving costly in the first set tiebreak against an Australian team buoyed by crowd support - but strong serving thereafter meant that neither were broken in the second set. The super-tiebreak found Ostapenko relentlessly going after the Polmans serve, smacking a clean backhand return winner to take the first match point.

Elsewhere, Barbora Krejcikova got her title defence off to a perfect start. The Czech, who won her first mixed doubles major last year here alongside Rajeev Ram but is now partnering Nikola Mektic as the No.5 seeds, overcame Kveta Peschke and Wesley Koolhof 7-5, 6-2 to set up a pop corn second-round clash against Amanda Anisimova and Nick Kyrgios. Meanwhile, 2019 women's doubles champion Samantha Stosur won her first Australian Open match in any discipline with Jean-Julien Rojer as the No.7 seeds dismissed Viktoria Kuzmova and Filip Polasek 6-1, 6-2. However, 2018 Wimbledon mixed doubles champion Nicole Melichar and her partner Bruno Soares fell 6-4, 7-6(4) to Nadiia Kichenok and Rohan Bopanna.

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