Clijsters has now won her last four matches against Williams
Kim Clijsters powered her way to the Sony Ericsson Open title in Miami and brought the winning run of Venus Williams to a shuddering halt.
The Belgian, 26, won 6-2 6-1 to secure her second title since coming out of retirement last year, the other coming at the US Open in September.
Williams, 29, went into the final on the back of 15 straight wins.
But she could not contain a rampant Clijsters, who needed just 58 minutes to win her 37th career title.
It is the second time that the Belgian has won the Miami tournament and she will rise to 10th in the world rankings on Monday.
I think sometimes you have to be careful with practice, not to practice too long. I may have made a mistake with that
Clijsters trailed 6-5 in head-to-head meetings going into the match but had won their only meeting - at last year's US Open - since ending her two-year spell in retirement.
And she came storming out of the blocks, grabbing breaks of serve in the third and fifth games on her way to wrapping up the first set in half an hour.
Williams, who had heavy strapping on her left knee and right thigh, needed to get a foothold in the match but Clijsters retained her stranglehold.
The Belgian expertly opened up the court to fire away a beautiful forehand for break point at the start of the second set and the pressure told on Williams, who double-faulted to give up the game.
Things got worse for the American two games later when a fizzing Clijsters return set up three more break points, before Williams hooked a woeful forehand into the tramlines to trail 3-0.
A second successive love service game followed for a now totally dominant Clijsters, who reeled off 17 points in a row during the middle of the set as she moved 5-1 clear.
And there was to be no late rearguard action from seven-time Grand Slam champion Williams as she fell 0-40 down, allowing Clijsters to break to love for the title.
"Of course she hit a lot of easy mistakes today, so it was just really trying for me to not lose my rhythm," Clijsters said afterwards.
"Whenever I had opportunities to step it up, I just really tried to do that. I was just really making sure that I was going for the lines and just kept her under pressure from there onwards."
Williams said: "I think sometimes you have to be careful with practice, not to practice too long. I may have made a mistake with that a little bit. I know better, but 'Eager V' kind of burst through.
"Overall I'm really happy with the tournament. Unfortunately, today I didn't win the match, although I felt like this is a match I could win. Unfortunately I made it a little bit too easy. Next time around I'll play better."