Holder Belinda Bencic ran off the first 19 points against Anastasia Pavlyuchenkova before collapsing to a 1-6, 6-1, 6-1 loss on Tuesday at the Dubai Championships.
Another former champion, the 2017 and 2018 winner Elina Svitolina, also fell, 6-2, 6-1, to US qualifier Jennifer Brady.
Pavlyuchenkova could not have made a worse start.
“It’s tennis, sometimes it happens,” the 31st-ranked Russian said "You go out there and you just don't feel anything.
“I just kept on fighting, still trying to hit every ball, trying to be there
“It doesn’t matter what the score is, just play. Slowly I started to turn it around, I started to find my game.”
“I honestly wasn't focusing on the score. Sometimes you can play amazing tennis and still lose 6-1. In the third set, it was a good level from both of us.”
Bencic, who is Swiss was seeded four and Svitolina third. That leaves the spotlight to tournament number one Simona Halep and second-seeded Karolina Pliskova, who begin in the second round after byes.
Weekend ATP Rotterdam winner Gael Monfils watched in pain as girlfriend Svitolina went down to Brady.
Svitolina had little to offer as the 52nd-ranked Brady gained her second victory this season over a Top 10 opponent after beating Barty in Brisbane.
