Germany's Julia Goerges crushed double Grand Slam winner Svetlana Kuznetsova 6-0, 6-1 to advance to the second round of the Dubai Tennis Championships on Monday.
The 55-minute demolition was eight-seeded Kuznetsova's heaviest defeat since suffering a similar scoreline last October in Wuhan, China.
The only two seeds playing in Monday's first round fell at the first hurdle with sixth seed and 2015 finalist Karolina Pliskova upset by American CoCo Vandeweghe who won her first match of the season 7-6 (7/5), 6-1 over the Czech wild card.
Goerges repeated history over Kuznetsova after beating the 18th-ranked Russian in the first round in Dubai four years ago on opening day.
"It was not one of my best," the 54th-ranked winner said. "I was very solid but I had a few mistakes.
"I didn't give her the chance to get into the match, I played aggressive."
Fellow German Andrea Petkovic also got off to a winning start, breaking six times in a 6-2, 6-1 defeat of Italian Camila Giorgi, to end a two-match loss streak.
The 28th-ranked Petkovic, who exited in the Australian Open first round, and then was beaten in the Fed Cup by Swiss Belinda Bencic, is working with a new coaching team and feels her tennis has turned a corner after she toyed with the idea of quitting the sport last December.
Petkovic could face new world number nine Bencic in the next round at the Aviation Club if the weekend finalist in St. Petersburg beats former number one Jelena Jankovic in the opening round.
The 40th-ranked Giorgi saved two match points in the final game as Petkovic closed out the victory in 63 minutes with 15 unforced errors to the 33 of her opponent.
"I'm very happy with how I played, I've worked hard over the past few weeks to be ready here and I was able to translate good training onto the match court," Petkovic said.
"All the work paid off, things are coming together for me."
Petkovic had a close call after the end of last season, as she pondered her future in the game. "I was in New York and thought about just staying there.
"But in the end I took my plane to Germany and began to work on my game," she said.
"I'm happy I made the right decision to stay in tennis."
Giorgi had won the first three matches between the pair, with Petkovic beating the Italian last season in Cincinnati.
"I didn't have the best head-to-head against her, but I'm finding the balance between consistency and going all out for your shots, coming in on the short ball - I think I did that quite well today," said Petkovic.
"I feel much more ready physically than I did last year and I'm looking forward to the season."
Kristina Mladenovic beat Lesia Tsurenko 6-2, 7-6 (7/1) while Frenchwoman Caroline Garcia put out Slovak Anna Karolina Schmiedlova 6-4, 6-1.
American Madison Brengle erased a 4-0 deficit in the second set to advance over Russian Ekaterina Makarova 6-4, 7-5.
The WTA field is headed by Romanian Simona Halep, with Spain's Wimbledon finalist Gabriela Muguruza the second seed.
The leading four seeds do not start until the second round thanks to byes.