WASHINGTON, March 26 (Xinhua) -- American veteran Venus Williams clawed back to defeat defending champion Johanna Konta from Britain in three sets in the fourth round to make last eight at the ongoing Miami Open on Monday.

After dropping a grueling first set, Williams recovered emphatically to cruise to a 5-7, 6-1, 6-2 victory in two hours and 21 minutes.

"The first set was definitely all her, and she came up with some amazing shots to break me at 5-5," three-time Miami Open champion Williams said. "There was not much I could do there, except just hope I could keep up in the second and third sets."

Coming off of a lengthy, three-set battle in her last match, which saw her have to save three match points against Dutch player Kiki Bertens, Williams understandably started her clash against Konta looking a bit sluggish.

But it was a different story in the second and third sets as Williams raised her level just as Konta seemed to struggle physically.

The victory is Williams' 64th Miami Open win, a run which dates back to her very first appearance at the tournament 21 years ago in 1997 and includes three titles -- in 1998, 1999 and 2001.

Up next, she will take on either Miami local Monica Puig or the on-fire American qualifier Danielle Collins for a spot in the semifinals.