Serena Williams needed less than an hour on court to secure her place in the third round at the Madrid Open, beating Sloane Stephens 6-4 6-0.

The world number one looked the stronger of the two Americans from the start as she broke her opponent's serve in the opening game of the match.

Stephens struggled to claim more than the odd point against the Williams serve, never threatening to get the break back as the top seed wrapped up the opening set.

After quickly racing to a 3-0 lead in the second set, Williams came under pressure as Stephens tried to get back into the match, bringing up two break points, but the world number one saved both before clinching the game.

Stephens was unable to recover, allowing her more experienced opponent to wrap up the final two games in just a couple of minutes.

Williams will face the winner of the match between Victoria Azarenka and Ajla Tomljanovic in the third round.