Bouchard, who reached the Wimbledon final as well as the last four at the Australian Open and French Open in 2014, dropped the opening set but recovered to send the match into a decider.

But Hradecká, ranked at number 85 in the world, held her nerve in the third set to see out a 6-4, 3-6, 6-2 victory.

“I'm so happy," the Czech said.

"It was definitely a tough match.

“I started very well, and then at the end of the first set, I started to be a little more nervy and tight."

Italian Francesca Schiavone is also out at the first time of asking as the 2010 French Open champion lost 7-5, 6-1 to Ecuadorian-born American Irina Falconi.

Dominika Cibulková of Slovakia, runner up at the 2014 Australian Open, managed to succeed where her fellow Grand Slam finalists had failed, though she was made to work hard for her 4-6, 6-1, 6-2 win over Sweden’s Johanna Larsson.

American Christina McHale beat Japan's Misaki Doi 6-2, 4-6, 7-5, and her reward is a clash with world number one Serena Williams of the United States in the second round.

In the men’s tournament, Germany's Alexander Zverev, who came within one point of eliminating Spain’s Rafael Nadal at the BNP Paribas Open at Indian Wells last week, is through to round two after he clinched a 7-6, 7-6 success against American wild-card Michael Mmoh.

“Today, with the changes in conditions compared to Indian Wells, it wasn’t easy to play the best tennis of my life," Zverev said.

"But I got through it, and I’m happy to be in the second round.

“I always knew Michael is a great player.

“He has a huge serve and he knows the conditions perfectly since he practices here."

Spain’s Fernando Verdasco and Mikhail Youzhny of the Ukraine, who both used to occupy places in the top 10 of the world rankings, are safely through after beating Gilles Muller of Luxembourg and Latvia’s Ernests Gulbis respectively.

Verdasco dispatched Muller 7-6, 6-3, while Youzhny ousted Gulbis 6-4, 6-2.

Men’s and women’s singles action in Miami continues tomorrow.