The 33-year-old warhorse, continually fending off retirement questions, partnered Chris Guccione to a 6-3, 7-6 (7/5), 6-2 victory over the Uzbek pair, Denis Istomin and Farrukh Dustov, to clinch the tie.
The 28-time Davis Cup champions were in an impregnable position after Hewitt and youngster Nick Kyrgios won Friday's opening singles in straight sets.
The Australians, playing on their favoured grass surface, have not dropped a set so far in the tie ahead of Sunday's dead reverse singles.
Hewitt, who took his 15-year career Davis Cup winning tally to 56 matches with 41 singles and 15 doubles, has faced a barrage of enquiries as to what his future holds, but he refuses to say.
The grizzled veteran, who has undergone five painful surgeries in five years in an effort to prolong his career including a knitting of the bone in his troublesome left foot, was his usual ferocious competitive self in Saturday's doubles.
Lleyton Hewitt talks with Chris Guccione in their Davis Cup doubles match. (Getty Images)
The Aussie pair took just 100 minutes to roll out their straight sets win in the doubles, shutting the door on Uzbekistan, who were bidding to reach the World Group for the first time.
Australia were forced in a play-off to retain their status in the elite 16-nation World Group after a first-round loss to France in February.
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