Williams was too good for rising star and fellow American Madison Keys, 7-6, 6-2.
While in the all-Russian clash, Sharapova crushed No.10 seed Ekaterina Makarova 6-3, 6-2.
The world No.1 was pushed to the limit in the opening set by Keys, who broke Williams in the opening game of the match.
However, Williams broke back a short time later and dominated the tie-break.
The second set was a lot easier for Williams who broke Keys twice to take control of the match.
Sharapova booked her ticket cruising by fellow Russian Ekaterina Makarova.
Sharapova won 6-3 6-2 but despite the match lasting 1hr 27 mins, it was a cakewalk for the 2008 champion.
She made fewer errors and used great depth of shot from the baseline to have Makarova under pressure from the opening games.
After some testing opening games, the world no.2 held a 3-0 lead in the opening set before taking it 6-3 in 48 minutes.
She had less trouble in the second set, sealing a berth in Saturday night’s decide.