Switzerland will return to the elite Davis Cup World Group next year after Stanislas Wawrinka sealed a 3-2 victory over Australia on Monday by wrapping up a five-set defeat of Lleyton Hewitt.
The pair were level at two sets each with Wawrinka leading 5-3 in the decider when the match referee decided it was too dark to continue late Sunday on the grass courts of the Royal Sydney Golf Club.
The pair resumed on Monday with the Swiss breaking Hewitt in the first game back to close out the match 4-6, 6-4, 6-7 (9-7), 6-4, 6-3, putting the visitors in the 16-team World Group in 2012.
For Australia, it means another year in the Davis Cup doldrums, forced to battle it out in zonal qualifiers for a chance to enter the elite competition again in 2013.
Hewitt came to the court on Monday with a heavily strapped right knee and was cheered by a small group of spectators who had turned up for the unexpected extra day.
He raced to a 30-0 lead but appeared to be struggling on court, with two double faults and two unforced errors ultimately costing him the game.
World number three Roger Federer had levelled the best-of-five tie at 2-2 when he beat Bernard Tomic in four sets 6-2, 7-5, 3-6, 6-3 on Sunday.
It followed Federer and Wawrinka losing their doubles rubber to Hewitt and Chris Guccione.
In the opening matches, Tomic beat Wawrinka while Federer won his clash with Hewitt.