Tashkent - Bernard Tomic clinched victory for Australia in their Davis Cup Asia-Oceania Group One second-round tie against Uzbekistan with a four-set victory over Denis Istomin on clay in Namangan on Sunday.
The 20-year-old downed Istomin 4-6, 6-2, 6-2, 6-3 in the fourth rubber to clinch Australia a place in September's World Group playoffs.
The 28-time Davis Cup champions are bidding to return to the competition's top tier for the first time since 2007.
Australia, captained by Patrick Rafter, went into Sunday's final singles leading the tie 2-1 after former world No 1 Lleyton Hewitt and Matthew Ebden won the doubles over Istomin and Farrukh Dustov, 7-5, 6-7 (4/7), 6-4, 3-6, 6-3 on Saturday.
Tomic, the highest-ranked player in the tie at 43, dropped the opening set against the 46th-ranked Istomin but took control and reeled off the next three sets for a convincing victory.
The youngster got Australia off to a winning start by beating Dustov, 7-6 (8/6), 6-4, 6-4 in Friday's opening rubber.