Hideki Matsuyama shot an even-par 72 on Sunday in the final round of the PGA Championship to finish the tournament at 1-over, seven strokes behind winner Phil Mickelson, who became the oldest player to claim a major title.

Mickelson won his second PGA Championship and sixth major at 50 years and 11 months following rounds of 70, 69, 70 and 73 which gave him a 6-under total at Kiawah Island Resort's Ocean Course.

Phil Mickelson of the United States celebrates after becoming the oldest major winner in golf history at 50 at the PGA Championship on May 23, 2021, on the Ocean Course at Kiawah Island in South Carolina. (Kyodo) ==Kyodo

He finished two strokes ahead of fellow American Brooks Koepka, who started the final round one shot behind Mickelson, and South Africa's Louis Oosthuizen.

Gunning for back-to-back majors following his historic Masters victory at Augusta last month, Matsuyama put himself in contention with a second-round 68 that left him two shots off the lead at the halfway mark.

Hideki Matsuyama acknowledges the gallery after sinking a birdie putt during the PGA Championship at South Carolina's Kiawah Island Resort on May 23, 2021. (Kyodo)

But his bid for the title effectively ended in the third round, when he plummeted into a tie for 23rd with a 4-over 76, four bogeys and a double-bogey on the back nine proving costly.

The 29-year-old from Japan shot four birdies against two bogeys and a double-bogey on Sunday to remain tied for 23rd.

"I couldn't get back into a flow easily. By the time I started playing a little better, it was already over," Matsuyama said.

"I'm very disappointed my game fell apart on the back nine of the third round."

The PGA Championship was Matsuyama's second tournament since returning from a month-long break after becoming the first Japanese man to win a major at the Masters.

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