MONTRÉAL, Canada - The unseeded Alizé Cornet has caused the first major shock of the Rogers Cup, bolstering her giantkilling reputation by ousting No.4 seed Angelique Kerber 6-4, 6-1.

Though the Frenchwoman has never been ranked in the Top 10, peaking at No.11 in February 2009, she has long been a thorn in the side of those who have: today's win is her 17th over a Top 10 opponent, including three over Serena Williams - her original first-round matchup this week. It also marks her second straight defeat of Kerber: having lost their first three encounters, Cornet captured her first win over the German 6-4, 6-4 in the second round of Beijing last year.

However, Cornet was careful today not to treat that victory as a winning formula. "I didn't adopt the same tactic last year in Beijing than today - I know also she improved herself in the last six months a lot," she explained. "Last year in Beijing, I was more focused about playing the forehand, moving her. It was different tactic today. It was more like playing on the backhand side, also being aggressive. It was different, and I'm happy I actually adapted my tactic depending on her, and that I could do it the whole match."

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The Wimbledon champion has been one of the most consistent players on Tour in 2018, with only one opening-round loss prior to this week (to Alison Riske in Mallorca). However, she began the match in uncharacteristically generous form, frequently committing sending routine rally shots long and into the net as her first-set unforced error total reached 20.

Afterwards, Kerber attributed her subpar play to rust and the surface change. "It was my first match after three weeks now," she explained. "It is always not so easy to change also the surface. I think I need a little bit more time to get used to hard court again, to have a lot of matches, a lot of practice sessions on hard."

Every so often, there would be a glimpse of Kerber's best tennis - her trademark forehand down the line to conjure up a break-back point when trailing 0-2, the relentless inside-out forehands and ferocious yell of celebration as she broke Cornet as the 28-year-old served for the set. But the former World No.1 was unable to parlay any of those moments into real turning points; on both occasions, Cornet simply responded to the loss of her serve by breaking again in the very next game.

The Gstaad champion, meanwhile, was putting on a display of canny, varied tennis. Unwilling to get dragged into long, drawn-out rallies with one of the best counterpunchers in the game, Cornet made judicious forays to the net whenever she could, and was able to put a number of key points away with emphatic drive volleys.

The World No.34's speed and anticipation also proved key: as the set drew on Kerber, unable to rely on her usual baseline weapons, deployed the dropshot with increasing frequency - perhaps too much, with Cornet successfully chasing down two to break the three-time major champion for a third time to seal the set.

This play also set Cornet on the right track as the second set began. Having been reeled back from 40-0 to deuce in her first service game, Kerber was once more threatening a momentum shift, hitting with increased aggression. But on the third deuce, the six-time WTA titlist showed off her deft touch to win one of the best points of the match, and followed it up with her first ace to hold - and immediately break a deflated Kerber en route to a 3-0 lead.

As the second set drew on, Cornet maintained her lead by cleverly mixing up her tactics: going after her forehand in one game as she raised her tally of winners to 20, retrieving everything Kerber could throw at her in another. The Frenchwoman's defensive skills were at their best in an epic sixth game: again, with her back to the wall, Kerber came up with some of her most aggressive plays as she attempted to stave off the double break, but the mini-battle ultimately went to Cornet on her sixth break point.

Having wobbled in her attempt to serve out the first set, a double fault and impatient errors added some drama to Cornet's match game - but she was also able to come up with a nerveless dropshot to reach her first match point. Yet another backhand over the baseline, Kerber's 32nd unforced error of the day, would seal the match for Cornet and add to her long list of big-name scalps.

Next up for the tenacious Frenchwoman is No.15 seed Ashleigh Barty - of whom she is a big fan. "I love this player, I love the way she plays," Cornet enthused. "I mean, it's so beautiful to see her play. I think she plays a little bit like a guy, with her forehand, big serve. She's not so tall, but she has such a big serve - I don't know how she does that. She's a different player, a little bit like Kasatkina. I like this kind of player that shows different things on the court: going to the net, slicing on the backhand side. It's nice because I'm also a little bit this kind of player that does a lot of variation in my game."

Cornet defeated Barty easily in the only previous meeting, 6-2, 6-1 in the first round of Roland Garros in 2014, but she pointed out that much had changed since. "She's definitely the favorite tomorrow, when I used to be the favorite [then]," she laughed.