Great Britain's Andy Lapthorne has won his fourth Australian Open wheelchair quads double title following victory in Melbourne today.
"I'm very pleased to now be a four-time Australian Open Grand Slam doubles champion," said Lapthorne.
"It's an amazing feeling and a lovely end to a tough couple of days."
Top seeds Lapthorne and Wagner stormed through the opening set, barely giving the number two seeds a chance to settle as they clinched it 6-0.
Despite leading 3-1 in the second, Alcott and Sithole dug deep to turn the tie around, winning five games on the bounce to level the match at one set apiece.
Wagner is not a three-time Paralympic champion for no reason, however, and he led the charge in the third and final set as the top seeds surged to a 6-2 victory in 37 minutes.
There was further success for British players in the men's and women's doubles contests with Gordon Reid and Jordanne Whiley each making it to the final of their respective categories.
Whiley joined with Japanese partner Yui Kamiji to defeat Germany's Katharina Kruger and Dutchwoman Sharon Walraven 6-4, 6-3 in the women's doubles.
The pair recorded a calendar Grand Slam last year after claiming victory in all four major tournaments and look well on their way to defending their Australian Open title tomorrow, where they face Dutch second seeds Jiske Griffioen and Aniek van Koot, who they beat in the Roland Garros, Wimbledon and US Open finals last season
Reid, on the other hand, partnered Argentina's Gustavo Fernandez to win their semi-final against second seeds Joachim Gerard of Belgium and Maikel Scheffers of the Netherlands 6-1, 7-5.
The pair will play defending champions and top seeds Stephane Houdet of France and Shingo Kunieda of Japan.
Houdet and Kunieda, world number one and two singles players respectively, will also take to opposite sides of the court in the men's singles final after both coming from a set down to beat Joachim Gerard and Fernandez in their respective semi-finals.
The women's singles final will see world number one Kamiji take on Griffioen.
Griffioen recorded a 6-4, 6-4 victory over compatriot and doubles partner Van Koot just hours before teaming with her to book a spot in the women's doubles final.
Kamiji secured her berth in the final with victory over Germany's defending champion Sabine Ellerbrock.
Ellerbrock had defeated the Japanese world number one in last year's final but went down 6-2, 6-1 in today's semi-final.
The round robin stage of the quad wheelchair singles also continued today, with Alcott upsetting American top seed Wagner 6-4 6-4, and Sithole defeating Lapthorne 6-3 7-6.
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