However after a 45 minute break during which both players left the court while the Rod Laver Arena's roof was closed due to the extreme Melbourne summer heat, Williams stepped up her tennis, hitting more winners and being more aggressive while Kuznetsova suffered a mental collapse.
Williams would win 5-7, 7-5, 6-1 to advance to Thursday's (not before 6:30pm PST USA tonight) semifinals versus the 4th seeded Dementieva also of Russia.
Williams, 27 years old and ranked 2nd could face a tough challenge from Dementieva, ranked 4th and also 27. Although Williams leads their head to head 4-3, Dementieva has won their last three meeting including a 6-3, 6-1 romp two weeks ago in Sydney.
Williams, Australian Open champion in 2003, 2005 and 2007, had trouble closing out the Summer Olympics quarterfinal versus Dementieva after taking the first set and leading in set two. Dementieva can rally with Williams, but her serve will not be a match if Williams is on top of her game.
Williams, however has been far from her best this year, after winning her 9th grand slam in September at the US Open. If too many errors appear today from Williams, Dementieva, who has won her last 15 matches, could win by a large part due to her striking baseline consistency. Dementieva this year won tournaments in Auckland and Sydney.
Dementieva will look to draw Williams into 20+ shot rallies and mix in her own winners and wait for the Williams error. Williams will attempt to keep points as short as possible and be aggressive with returns and serves to put herself into a winning position.
Both players have only dropped one set in the singles tournament. But Dementieva may be the fresher physically of the two. Williams' doubles play this week with her sister Venus Williams may come back to haunt her if she suffers fatigue during a decisive third set.
In the second women's semifinal to be played today, 7th seeded Vera Zvonareva meets the 3rd seeded Dinara Safina in an all Russian matchup.