Federer won his first 12 matches against Davydenko but was under pressure Wednesday after losing their last two meetings: at London in November and at the season-opener at Doha earlier this month.
The 15-time Grand Slam champion rebounded after falling a set and a break behind against Davydenko, winning 13 straight games to take control of the quarterfinal on Rod Laver Arena.
Story continues below ↓advertisement | your ad hereFederer has ensured he'll be at No. 1 for a 268th week when the new rankings are released Monday, equaling Jimmy Connors in third place on the all-time list.
No. 3-ranked Novak Djokovic lost to Frenchman Jo-Wilfried Tsonga in an Australian Open quarterfinal that reversed the result of their final here two years ago.
No. 10-seeded Tsonga won 7-6, (8), 6-7 (5), 1-6, 6-3, 6-1 in the Wednesday night match, consigning 2008 champion Djokovic to quarterfinals exits in consecutive years.
Djokovic took a medical timeout after going down 2-0 in the fourth. He'd just dropped a service game in which he clutched at his stomach and struggling to breath.
Tsonga took control of the remaining two sets and moved into a semifinal against top-ranked Federer.
Djokovic retired in the fourth set of his 2009 quarterfinal against Andy Roddick due to heat-related illness.
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