Muguruza came from one set down to defeat Yastremska 4-6, 6-3, 6-3 in her opening match of the Women's Tennis Association Premier 5 event at the Aviation Club Tennis Centre in Dubai. 

The Spaniard had lost her last two encounters with the Ukranian.

"It’s not easy when you lose the first set, you’re kind of a little disappointed, and I managed to forget about it," said Muguruza. 

"It doesn’t happen every day, and I’m happy with the three-set win. 

"I think all of these matches are going to count at the end of the year."

Muguruza is now set to play Zheng Saisai in the next round, with the Chinese player beating Australia's Ajla Tomljanović 6-2, 4-6, 7-5. 

Kristina Mladenovic of France comfortably won her match against wildcard Fatma Al-Nabhani of Oman 6-1, 6-1.

She has now set up a clash with world number one and US Open and Australian Open champion Naomi Osaka of Japan, who received a bye into the second round.

Canada's Eugenie Bouchard defeated Vera Lapko of Belarus 6-3, 6-4 to set up a tie against Romania's Simona Halep, who yesterday lost the final of the Qatar Open.

The remaining first round fixtures will be played tomorrow, when other top seeds, including Karolína Plíšková and Petra Kvitová of the Czech Republic, are due to join the competition.