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There was a sea of fans present when Phil Mickelson and Brooks Koepka walked down the fairway to the green on the 18th hole of Sunday's PGA Championship. Following Mickelson's approach landing on the 18th green, marshals and security made an attempt to protect both Mickelson and Koepka from the spectators.

On Tuesday, PGA of America CEO Seth Waugh issued an apology for the chaotic scene and said that the scene "made two players and their caddies feel vulnerable."

Waugh also added that scene resulted from "a moment of high elation and pent-up emotion by spectators," and ended up overwhelming the security staff.

At 50 years old, Mickelson became the oldest player to ever win a major championship on the PGA Tour and it marked the sixth major title of Mickelson's career. Koepka and Louis Oosthuizen finished tied for second behind Mickelson.

Koepka was very outspoken regarding the scene and even wondered if someone was purposely trying to hurt him. The runner-up had his knee surgically repaired back in March.

"I don't know, it felt somebody tried to ..." Koepka said. "I don't know what the deal was, but it's what it is."

Waugh also said that the safety of the participants is always the chief goal and was glad that no one was injured during the frenzy. Fans did crowd around the 18th green to celebrate Mickelson's win.