The 20-year-old fell just short at last year’s tournament as she lost in a playoff to Canada’s Brooke Henderson at Olympia Fields Country Club in Illinois.

Back then, Ko was the top ranked player in the women’s golf world.

However, the Rio 2016 Olympic Games silver medallist has dropped a couple of places down the leaderboard, sitting behind South Korea’s So Yeon Ryu and Ariya Jutanugarn of Thailand.

Looking ahead to this year’s competition, which starts at the Olympia Fields Country Club in Illinois, Ko said that even though she is no longer top of the pile, she is still under pressure.

“You know, there might be a little less pressure because some of the other girls are playing in such a great standard,” she said.

“But I don’t feel like a lot of things have changed.

“It’s only been a few weeks and all of the changes that have happened.

“But with the rankings and how well all the girls are playing, you never know exactly what’s going to happen and in one week things can change.”

Ko is due to head out in the opening round at 1.50pm local time tomorrow and will begin on the ninth hole in an interesting group featuring South Korea’s Inbee Park, the Rio 2016 gold medallists and a three-time winner of the tournament.

They will also be joined by Lexi Thompson of the United States, who was controversially handed a four-stroke penalty at the ANA Inspiration earlier this year after someone watching on television spotted a rule infringement from the 22-year-old which had been missed by tournament organisers.

Defending champion Henderson will be among the earlier starters, setting off at 8.40am alongside Jutanugarn and Alison Lee of the US.

Current world number one Ryu will be part of the group starting on the ninth hold at 1.40pm with American golfer Gerina Piller and Norway’s Suzann Pettersen.

The final round is due to take place on Sunday (July 2).