Serena Williams overcame Li Na in straight sets to win the Sony Open title for a seventh time in Miami.

The 32-year-old world number one, who defeated Maria Sharapova in their semi-final clash on Thursday, claimed a 7-5 6-1 triumph over her Chinese opponent in just under two hours.

The final was Williams' ninth at the Sony Open.

Li opened a 5-2 lead in the first set before the American fought back to take it 7-5.

And Williams carried her momentum into the second set, leaving the world number two struggling as the eventual winner won 11 of the last 12 games to seal the victory.

Williams was delighted with her win and thanked her fans for their support.

She told the WTA website: "It was a really important victory, especially playing Li Na, who has been playing so well

"She started out so well - I was like 'oh my gosh, I just need to hang in here'.

"Then I heard some fans trying to pull me through - if it hadn't been for you guys I wouldn't be standing here right now."

Li was disappointed with her loss and praised her opponent before thanking her team.

She said: "I have to say well done to Serena - you had a very good two weeks here.

"Keeping healthy is the most important thing for me, and just trying to do the best I can.

"Of course I want to thank my team as well."