Serena Williams returned to tennis in the same fashion she left - as a champion.

After missing eight months with a knee injury, Williams captured her third straight NASDAQ-100 Open title, completing her comeback with a 6-1 6-1 thrashing of fifth-seeded Russian Elena Dementieva in Miami.

"I'm real happy that I was able to come back and take a title," Williams said. "I just came out and wanted to win every match or just win every point.

"The win just says I'm back. As long as I'm healthy, then I'm definitely still a top competitor."

Prior to this event, Williams had not played a tournament since winning her sixth Grand Slam crown at Wimbledon in early July.

She was then ranked number one in the world, but has been overtaken by Belgium duo Justine Henin-Hardenne and Kim Clijsters after undergoing knee surgery on August 1.

Williams delayed her return on doctor's orders, but questions arose as to her commitment to tennis after she appeared in cameos in television series and a fashion show.

However, the 22-year-old American silenced her detractors with a dominant performance in this tournament.

She needed just 50 minutes to dispose of Dementieva, who had eliminated older sister Venus in the semi-finals, and lost only one set in six matches.

Williams became the first woman in eight years to claim the title in three consecutive seasons - Steffi Graf achieved the feat from 1994-96.

Dementieva, trying to become the fifth woman to topple the Williams sisters in the same event, was overwhelmed in the final.

She lost her serve seven times, committed nine double faults with no aces, and made 23 unforced errors with only 11 winners.

"It's unbelievable to me (that Williams can play so well in her return)," Dementieva said. "She was very strong on the court, moving well.

"She had a couple of problems in the second round, but she came through very strong. She's a great player."