Tournament favourite Caroline Wozniacki has been sent packing from the Charleston Open.

The former world No.1 was upset 6-2 6-4 by Latvia’s Jelena Ostapenko in the quarter-finals on Friday.

Wozniacki was the highest remaining seed in the tournament, having won two matches on a windy Thursday which included a win over Australian qualifier Anastasia Rodionova.

Her second-round match was rained out on Wednesday, forcing her into double duty. She was the lone former champ left in the draw.

“Yeah, it feels amazing,” Ostapenko said. “I just knew before the match that I have to stay aggressive all the time and still be consistent.

“And I tried not to step back, just to be like – play in the court all the shots. And I think that’s helped me today.”

Ostapenko converted 22 of 30 first serves (73 per cent) and saved four of five break points against Wozniacki.

“I really tried my best out there,” the Danish star said. “I was trying to grind everything down.

“I tried to change the pace when I had the opportunity, but I mean, if she played like this every day, then I mean she would be No. 1 in the world.

“You know, she really played well. She went for her shots. Everything was going in. She was hitting the lines. Everything that could go her way today was going her way.”

In other quarter-final action on the green clay at Daniel Island, Mirjana Lucic-Baroni of Croatia beat hometown favourite Shelby Rogers in three sets.

The 35-year-old Lucic-Baroni, the oldest player left in the draw, rallied after a tough first set to win 6-7 (9-7) 6-1 6-1. She had never been past the round of 16 before.

In the other matches, Russia’s Daria Kasatkina beat Irina-Camelia Begu of Romania 6-4 6-1 and Laura Siegemund of Germany beat Latvia’s Anastasija Sevastova 6-2 6-4.