The glamorous Russian, on the comeback trail from a shoulder injury that forced her off the tour in August, battled past the tough American 6-3, 6-4 but her game was marred by too many errors and a serve that failed to fire.
"After (missing) my last Grand Slam in New York I have been so looking forward to this one and I was really happy to start," she said.
"I have had trouble against her in the past and I knew it would be no different tonight."
The four-time Grand Slam winner, in a powder blue dress, only made her return at the Brisbane International this month where she lost to bitter rival and eventual champion Serena Williams in the semi-finals.
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Sharapova, who was using an ice vest even at 11:00 pm after a scorching hot day, won't be relishing a possible final meeting with Williams, who has a 15-2 record in their career meetings.
She was playing aggressive tennis and forcing errors from the American, which cost her dearly with the third seed racing to a 4-0 lead.
But the colourful Mattek-Sands, sporting purple dyed hair and her trademark knee socks, forced her way back into the game when Sharapova drove a forehand long to give her a glimmer of hope.