Seven-time Grand Slam champion Venus Williams fell out of the Australian Open at the first hurdle on Monday after a marathon clash with Russian 22nd seed Ekaterina Makarova. (Click here for latest on Australia Open)
The former world number one was unseeded in Melbourne despite playing 11 events last year and making three semi-finals, and she looked on course for victory after winning the first set.
But a series of unforced errors and failure to convert crucial break points cost her dearly and she was sent packing 2-6, 6-4, 6-4 after a nearly two-and-half-hour epic in blazing hot conditions.
Williams hasn't won a Grand Slam since Wimbledon in 2008 and is without a title since Luxembourg in October 2012, but she made the final of the warm-up Auckland International, losing a three-set final to Ana Ivanovic.
It put her in good stead for Melbourne but after being diagnosed with energy-sapping Sjogren's Syndrome in 2011, and adopting a raw foods diet to ease her symptoms, she pulled out of last week's Hobart International to rest.
It appeared to pay dividends as a fresh Williams got an early break to go 2-0 up before the Russian immediately broke back.
Williams is seeking to stay in touch with the game's elite after two years marred by battling illness and injury, and her trademark booming serve was firing.
She was also returning well and sent some sizzling winners off her backhand to secure two more breaks and take the first set 6-2 in 31 minutes.
Despite searing heat on Margaret Court Arena, Williams was looking set and should have gone 5-2 up in the second but she threw away two break points and then lost her serve to be 4-3 behind.
She fought back to win the decisive next game on her fifth break point to level at 4-4, only to lose her next serve and then the set on a series on unforced errors as the pressure mounted.
Williams took an extended off-court break between sets to regroup, returning to race to a 3-1 lead in the third before a wild backhand allowed the Russian back into the match.
Williams was broken again to go 3-5 down and there was no way back as Makarova served out the match to line up a second round clash with American Irina Falconi, who beat Spain's Anabel Medina Garrigues.