First came the terrific defensive backhand on a high, heavy shot that caught the back corner of the court - vintage stuff.
But the truly eye-catching bit was the follow-up: a headlong cross-court sprint from behind the baseline to retrieve a drop shot and dink it down the line for a perfectly placed winner.
No one reaches No. 1 in the world without being able to make a shot or two.
It may be imprudent to draw too many conclusions from a 6-1, 6-0 blowout win, but Caroline Wozniacki's ruthless dismantling of American qualifier Shelby Rogers ("who took out local favourite Eugenie Bouchard in the second round), her first match of the week ("a 6-1, 6-1 demo job on former top-five player Daniela Hantuchova) and a recent tournament victory in Turkey suggest a bit of a trend.
After a two-year fallow spell in which she didn't win more than one tournament in any single season - having won a total of 15 from 2009-11 - the 24-year-old Wozniacki is surging at a venue where she is now 9-1 in her career.
There are seven players at this week's Rogers Cup in Montreal who have previously occupied the top ranking in women's tennis - as well as the current No. 1, Serena Williams - Wozniacki is the only one among them who hasn't won a title of any kind at a Grand Slam.
The tall Dane is, however, set for the quarter-finals of a tournament she won four years ago - the same can't be said of Maria Sharapova, another former No. 1, who bowed out in three sets against Spanish player Carla Suarez Navarro ("the 14th seed).
"I couldn't find my rhythm from the beginning of the match," the fourth-seeded Sharapova said afterward.
It wasn't the day's only upset: Wimbledon champion Petra Kvitova, the second seed, fell to 19thranked Ekaterina Makarova in three sets.
A few hours later Jelena Jankovic, another member of the exclusive No. 1 club, lost to qualifier Coco Vandeweghe ("51st in the world rankings), also in three sets.
Serena Williams, the top seed and defending champion, managed to overcome Lucie Safarova in straight sets, she'll now match wits with Wozniacki in the quarters; Williams has won six of the seven meetings between the two, but the latter has found a rich vein of form.
The knock on Wozniacki has traditionally been that she doesn't serve as well as the elite players and has no standout elements to her game.
No one who watched Thursday's match will have come away thinking either of those things.
Against Rogers, Wozniacki landed 85 per cent of her first serves ("winning all but six of 34 points) and won 24 of 36 return points, including 10 of 13 on Rogers' second serve.
She roared out to a 4-0 lead in the first set ("taking a zippy 26 minutes to do so) before a rain shower interrupted the match for 30 minutes; it didn't break her rhythm.
It's natural to point to Wozniacki's high-profile split with golfer Rory McIlroy last spring as the catalyst for a revival - it's not a subject she cares to explore publicly, and earlier this week she said "I've moved on ... I would like everyone else to move on too."
Personal circumstances might have some bearing on her recent play, but it's also due to paying particular attention to her serves and return game.
Asked about the specifics of what she's done, she said, "I've just served a lot and returned a lot, really.
"You kind of just get that feeling; you get in the zone. You know that you can pull it out when you need to," she said. "I think that's really the key, just repetition, repetition all the time."
Wozniacki is ranked an eminently respectable 12th in the world these days, Hingis, Venus, Sharapova, Serena, Ivanovic, Jankovic, Azarenka, all former No. 1s at the tournament.