Veteran Hsieh and Poland's Zielinski overcame Great Britain's Neal Skupski and American Desirae Krawczyk in a thriller on Friday that was decided by a 10-point tiebreak 6-7 (5-7) 6-4 11-9.
Hsieh is also into the women's doubles final after she and Elise Mertens downed Australia's Storm Hunter and her Czech partner Katerina Siniakova in the semi-finals.
They will face Ukrainian Lyudmyla Kichenok and Jelena Ostapenko of Latvia in the decider.Â
Coached by Australian doubles great Paul McNamee, Hsieh became a crowd favourite at Melbourne Park back in 2021 when she made an unlikely run to the singles quarter-finals before being eliminated by eventual champion Naomi Osaka.
While it is Zielinski's first grand slam title, 38-year-old Hsieh is celebrating her seventh, having previously won six women's doubles majors, including Wimbledon on four occasions. It is her first title in Melbourne.
Having never played in a grand slam together, Hsieh and Zielinski found each other at the last minute on a sign-up list for the Open.
Their FIRST Grand Slam mixed doubles title as a team �— #AusOpen (@AustralianOpen) Congratulations, @SuweiHsieh @zielaczekk#AusOpen • #AO24 pic.twitter.com/htx5iM99SKJanuary 26, 2024
Skupski and Krawczyk were aiming for their third major title after twice winning the mixed doubles at Wimbledon.
After the teams shared the opening two sets, the title was decided by a 10-point tiebreak, with Hsieh and 27-year-old Zielinski getting off to a flyer to lead 7-4.
After levelling at 8-8, Skupski stepped up to send down two timely aces to set up a championship point at 9-8.
But their rivals kept their cool, Hsieh saving the day with a fierce volley at the net.
They set up their own match point on Krawczyk's serve, with Skupski putting Zielinski's return into the net.
Zielinski lost the men's doubles final last year and only signed up for mixed as an after-thought.
"I didn't know until the last minute who am I going to play with," he said.
"I was coming into Melbourne not really aiming for the mixed doubles after losing in the first round last year, so I was coming in just to have fun.
"When I saw Su-Wei's name on the looking list, I thought this could be the best partner I ever had so let's text, and she agreed on the same day."
Hsieh said her first mixed major title felt special.
"With mixed doubles, it was exciting and my partner is very good - I know he's very good from the baseline, at the net, and the serve,'' she said.Â
"I just need to do my stuff to put the ball inside the court and pass the net person.Â
"He's doing his job, so I'm doing my job and we're doing good."
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