KEY BISCAYNE, Fla. — Danielle Collins was 6 years old when Venus Williams won Wimbledon for the first time, in 2000. Collins was just beginning to play tennis at the time, and for most of the next two decades Venus and her sister Serena Williams would provide inspiration for Collins, who is now one of the fastest-rising young Americans on the women’s tennis tour.

On Wednesday, in her home state, Collins will play the biggest professional match of her career, squaring off against Venus Williams in the quarterfinals of the Miami Open. It is yet another big step in an impressive year for Collins, who also won a tournament in Newport Beach, Calif., in January and reached the round of 16 at the BNP Paribas Open in Indian Wells, Calif.

Now she will face a woman she imitated as a young girl, smashing tennis balls against a backboard and begging adults to play with her on the public courts of St. Petersburg, Fla. But don’t expect Collins, 24, to be in awe of the player across the net.

Brimming with confidence and stiffened by the experience of playing at, and graduating from, the University of Virginia, Collins, a two-time N.C.A.A. singles champion, is unsurprised by her recent emergence.