Muguruza, beaten by Williams in last year's Wimbledon final, turned the tables to win the French Open on Saturday and climbed to a career-high second on the WTA list.
Should she win the Wimbledon title and the 34-year-old Williams loses before the final, she would rise to number one, a position Williams has held for 178 weeks.
"Everybody's dreaming about being number one," 22-year-old Muguruza said after her straight sets defeat of Williams.
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"My focus is just on winning matches and tournaments. But of course I would be very happy to be number one."
The last Spanish woman to reach the number one ranking was Arantxa Sanchez Vicario in 1995.
Muguruza will prepare for Wimbledon at the inaugural Mallorca Open starting next week, the first grasscourt tournament ever held in Spain.
(Reporting by Martyn Herman; Editing by Robin Pomeroy)
