More comfortable on hard courts than clay, Sloane Stephens started her spring campaign on the red dirt at a small tournament in Bogota, Colombia.  Unfortunately for the top American woman outside Serena Williams, her week in Bogota lasted just 65 minutes.

Stephens fell in straight sets to home favorite Mariana Duque-Marino, a woman with greater clay skills but much less impressive credentials overall.  In fact, Duque-Marino had not won a WTA main-draw match since Wimbledon last year, and her ranking has languished outside the top 100.  Stephens also had won their only previous meeting on red clay in Morocco three years ago.  The American has improved her clay comfort level since that time, even reaching the second week of Roland Garros last year, so this upset came as a surprise.

Unable to protect her serve, Stephens won only four second-serve points and saved just two of six break points.  The match marked the fourth opening-round loss that she has suffered in six tournaments since the Australian Open.  Injury played a role in her February setbacks, but Stephens seemed to have regained her fitness ahead of an encouraging quarterfinal run at Indian Wells.  Starting with a flat effort against Caroline Wozniacki in Miami, however, she has lost six consecutive sets.

The Bogota draw may open for Duque-Marino to thrill her compatriots with a strong passage of play.  The Colombian won her home tournament four long years ago for her only career title to date.  Memories of that achievement may have inspired her in her upset over Stephens.  Like Jana Cepelova in Charleston and Kimiko Date-Krumm in Monterrey last week, she now faces the equally imposing challenge of building on her breakthrough.