The No. 3 seed won the match 6-2, 6-1 against the No. 28 seed. Muguruza will face top seed Simona Halep in a semifinal matchup at 9 a.m. Thursday on Court Philppe-Chatrier at Roland Garros.
"On paper it's a step in the right direction," Sharapova told reporters. "It's tough to just assess a singular tournament. I think I have to put a lot of things in perspective for the last four or five weeks."
Sharapova advanced into the quarterfinal matchup after Serena Williams withdrew from the tournament on Monday, giving her a victory in the round of 16. Muguruza beat Lesia Tsurenko, who retired due to an injury in the first set during their round of 16 clash.
Halep beat Angelique Kerber in three sets to advance to the semifinals. Americans Madison Keys and Sloane Stephens will also play for a spot in the finals on Thursday at Roland Garros.
Sharapova, 31, won her last Grand Slam at the 2014 French Open. She also won at Roland Garros in 2012. Sharapova has five career Grand Slam titles.
Muguruza, 24, is ranked No. 3 in the world by the Women's Tennis Association. She won Wimbeldon in 2017 and the 2016 French Open.