Some players wear their heart on their sleeve. Venus Williams' heart was whizzing around the back of her neck like a runaway hoola hoop seven games into her match with Paula Ormaechea.

The heart-shaped pendant Williams wears on a chain was swirling as she careened around the court, chasing shots from the 120th-ranked Argentine upstart. But while Williams' heart may have been racing, her head was clear. Playing with a placid expression, Williams ravaged Ormaechea's second serve in winning the final three games to close an entertaining 4-6, 6-1, 6-3 victory.

Despite a cluster of clouds that dimmed the late-afternoon sun, Ormaechea, who has succeeded Gisela Dulko as Argentina's top-ranked woman, came out wearing Oakley sunglasses and smacking eye-opening groundstrokes in the opening set. The Buenos Aires-baseliner stood toe-to-toe with Williams and often took charge in early exchanges.

Running around her backhand, Ormaechea struck a forehand return winner up the line that a flailing Williams could not control to break for 2-1. Ormaechea's strokes are her strength—she hits bold strikes with spin and opened the court with crisp combinations, leaning into a forehand to break again for 5-2 before closing the opening set in her main-draw debut.

The pace and depth of the 5'7" Argentine's shots seemed to take Williams by surprise, but she recalibrated and came out recharged in the second set. Serving with more authority, taking the first strike in rallies, and playing her cross-court forehand with greater depth—rather than trying to pull the trigger prematurely down the line—Williams roared back, patiently pounding Ormaechea into submission to take a 5-0 second-set lead. Venus' legs and her defensive skills are two of her most underrated assets, and she used both to extend rallies with the 19-year-old, playing just her third major match. In a declarative serving performance, Venus won 16 of 19 points played on her serve in the second set to level the match.

There's a lot to like about Ormaechea—she's quick around the court, fearlessly attacks her ground strokes, can change direction off both wings, and plays with plenty of positive emotion, fist-pumping frequently. She also didn't wilt after Williams pulverized yet another down-the-line return winner to break for a 3-2 lead in the decider. Ormaechea was two steps off the doubles alley when she lashed a running forehand winner down the line to break right back for 3-all.

That shot may have rattled even some veterans, but Williams barely blinked beneath her black visor. She smacked successive backhand return winners down the line and followed with an inside-out forehand return winner to break, again, for 4-3. Ormaechea did not win a point on her second serve in the final set.

Using a slick backhand swing volley to consolidate for 5-3, Venus slid into a forehand return that slipped over the net to seal the win, setting up a possible second-round blockbuster with third-seeded Agnieszka Radwanska.

—Richard Pagliaro