The Russian world number 56, who had not won a main-draw go with since last August before returning in Victoria, was predicted to offer little more than an impediment for the five-time champ.
But she instead the unheralded Makarova, 23, who had previously irritated 7th seeds Notara Zvonareva, sent the National excellent providing for one of her most severe failures at a fantastic throw competition.
Makarova smashed five periods as she outplayed a below-par Williams, who has not missing to such low-ranked weight at a throw since Wimbledon 2005, when she missing to community variety 85 May Craybas.
Makarova will perform either other countrywoman Nancy Sharapova or Germany's Sabine Lisicki in the last eight, but said she wasn't considering too far forward.
"I will check out the experience today," she said. "I performed a several periods against Sharapova and a while ago against Lisicki. They are excellent gamers.
"(But) I don't want to think about the next go with. I just want to savor this moment in time."
The European is now into her first fantastic throw single men and women quarter-final, which would have seemed an impossible probability when she missing in the first circular at six immediately tourneys in one more several weeks of last period.
This period, Makarova came through determining at the Quotes Worldwide, but then missing in the first circular to China's Li Na. But she has now regular Tamarine Tanasugarn, Kaia Kanepi, Zvonareva and Williams in Victoria.
"I didn't perform that excellent the second 50 % of the period. In the end of the period, I missing six tourneys first circular," she said. "That was last period. This is the new period, new sensation, new activity. It's different.
"I had a excellent vacation, didn't think about golf. And then I had a excellent planning, practised so challenging with my instructor and my actual instructor so I think that the outcomes present that I proved helpful challenging."
Almost from the first factor of Monday's go with it became apparent that Williams, who seriously injured an ankle joint this 30 days in Queensland, was not her regular self as problems came large and quick from her racquet, 37 in all.
The 30-year-old's activity was also inadequate and she often didn't try to pursuit large paintballs. In comparison Makarova was seeking everything and awaiting the almost predictable problems.
"I'm amazed because she is an excellent gamer and it's really hard to perform against her, but I don't know I just experience so excellent and so targeted," she said. "So I performed my activity and that's it. I won against Serena. That's awesome."
Makarova won the operator in 31 moments, but Williams seemed to get elements under control with an beginning separate in the second -- only to give up it the next activity.
Makarova presented offer to stage the set at 2-2, then smashed again as a disappointed Williams offered a sequence of double-faults.
The European with assurance shifted to a 5-3 cause, before fighting Williams' offer and bursting for a amazing success.
Makarova achieved a career-high standing of 29 last June but the sequence of inadequate outcomes saw her decrease out of the top 50.
