In just her second season on the LPGA Tour, Ko Jin-young can call herself a major champion.

The South Korean won the ANA Inspiration in Rancho Mirage, California, on Sunday (local time), at 10-under 278, three shots over fellow South Korean Lee Mi-hyang at Dinah Shore Tournament Course at Mission Hills Country Club.

Ko carded a 70 in the final round, mixing five birdies with three bogeys. She led comfortably for most of the day, though a pair of bogeys on the back nine saw her lead trimmed to one briefly.

This was Ko's first major title. Her previous best showing had been a runner-up finish at the 2015 Ricoh Women's British Open, when she was still a Korea LPGA member.

Ko, 23, won the 2018 LPGA Rookie of the Year honors. In five starts this season prior to the ANA Inspiration, Ko already had a victory and three other top-three finishes, while taking the LPGA lead in money ($552,273) and the Player of the Year points race (63).

The world No. 5 took home $450,000 to become the first player to surpass $1 million in earnings this year.

South Korean players have won five of the eight LPGA tournaments so far this season.

Ko could soar to world No. 1 when the new rankings are announced early Tuesday (Korean time). The LPGA Tour has shied away from projecting rankings of tournament winners, after miscalculating rankings points and erroneously announcing that Ariya Jutanugarn was about to supplant Lydia Ko as world No. 1 in June 2017.

South Korea's Park Sung-hyun is currently No. 1 with 7.06 points, and Ko has 5.62 points. The world rankings evaluate a player's performance over a rolling two-year period weighted in favor of the current year, and an extra emphasis is placed on the most recent 13 weeks.

Ko opened the final round nursing a one-shot lead over countrywoman Kim In-kyung. Ko opened a two-shot advantage with a birdie at the second, while Kim fell further back with a bogey at the third.

Lee Mi-hyang was making a run in the penultimate pairing with a birdie-birdie start that put her at seven-under.

Lee took a step back with a bogey at the seventh, while Kim didn't make up any ground with six consecutive pars to make the turn at six-under. Ko had a birdie at the fifth and a bogey at the eighth to find herself at nine-under through the first nine holes.

A double bogey at the 11th took Kim out of contention, while Lee tried to put some pressure on Ko with a birdie at the 12th.

Ko picked up her third birdie of the day at the 11th to hold a three-shot lead over Lee at 10-under.

Ko stumbled a bit down the stretch, as bogeys at the 13th and 15th dropped her to eight-under, just one ahead of Lee with three holes to play.

Ko bounced right back with a birdie at the 16th while Lee missed some birdie opportunities over the final few holes.

Standing on the fairway at the par-5 18th, Ko watched Lee pick up par at the finishing hole and end her tournament at seven-under.

With a two-shot cushion, Ko laid up and reached the green in three.

Only needing to avoid a catastrophe on the green, Ko drained the long birdie putt to cap off her maiden major.

 Ko, the 2016 KLPGA Player of the Year, had nine career wins on the domestic tour when she claimed her first LPGA victory at the KEB Hana Bank Championship on home soil in October 2017. That gave her exemption for the LPGA Tour for 2018, and Ko won her first official LPGA start in February last year at the ISPS Handa Women's Australian Open. She became only the second player in LPGA history to win in her debut.

After handily winning the top rookie honors in 2018, Ko got off to an impressive start in 2019. She finished second in her title defense at the Australian Open. After tying for 29th in Thailand, Ko contended again the following week in Singapore, tying for third at the HSBC Women's World Championship.

Ko then earned her first win of the season at the Bank of Hope Founders Cup on March 24. The very next week at Kia Classic, Ko tied for second place.

Then came the ANA Inspiration. Ko shot 69-71 in the first two rounds to stay four behind the 36-hole leader, Kim In-kyung, and leapfrogged the South Korean veteran with a 68 in the third round to build a one-shot lead that she would never relinquish.

Ko is the fifth South Korean to win the ANA Inspiration, and the 15th South Korean to win an LPGA major. (Yonhap)