World No.1 Ko Jin-young pulled away from second-ranked Kim Sei-young with five back-nine birdies on Sunday to win the Ladies Professional Golf Association's (LPGA) season-ending Tour Championship by five strokes.

Ko, who was playing just her fourth LPGA event of the pandemic-disrupted season, had only squeezed into the elite field with a tie for second on Monday at the U.S. Women's Open.

But the 25-year-old South Korean made the most of her opportunity, firing seven birdies in her six-under par 66 at Tiburon Golf Club in Naples, Florida.

She rolled in a final birdie at the 72nd hole for an 18-under total of 270 and a convincing win over Kim and Australian Hannah Green, who shared second on 275.

The $1.1 million winner's prize – down from $1.5 million last year but still the biggest in women's golf in 2020 – put Ko atop the money list for the year.

Her $1.66 million in earnings in 2020 saw her top the $5 million mark for her career.

It was the payoff for the lonely weeks since she returned to the U.S. in November, leaving family and friends back in South Korea.

"Last week I had really good round and then I finished top two, so and then I can play here," Ko said.

Kim, whose two victories since LPGA play resumed after a pandemic shutdown included a first major at the Women's PGA Championship, had come into the day with a one-stroke lead.

Unable to build momentum in an even par round that featured three bogeys and three birdies, her share of second was enough to overtake veteran South Korean compatriot Park In-bee for Player of the Year honors under the points system used by the LPGA.

Park finished in a tie for 35th.

Ko and Kim played together in the final group, but the duel between the world's top two turned into a lopsided affair.

"We are close, so, yeah, it was tough," Ko said of again playing alongside good friend Kim.

"But it was competition ... so I say a little sorry to Sei-young. She played good, I played a little better."