Mickelson took a deep breath and swung, but got over the top too much and pulled his shot into the massive sand pit to the right of the green.
Mocking boos rained down as if this were the Stadium 16th green at TPC Scottsdale.
"Darn it!" Mickelson said to himself in a scolding tone.
The crowd made up for its prickliness with a rendition of "Happy Birthday" for Mickelson celebrating his 45th on Tuesday, but there's clearly a mixed message of confidence and frustration.
There are the expectations that come from a sea of supporters because Mickelson is a five-time major winner and one of the most popular golfers of all time. He is "Phil the Thrill," after all.
Then there is the reality, which has seen him mostly scuffle around courses in the nearly two years since he captured the third leg of the career Grand Slam with a surprising
This week's U.S. Open is Mickelson's second chance to become the sixth player to complete the Masters-era career Slam. He wasn't close last year at Pinehurst in tying for 28th.
"I still have a huge obstacle, a huge challenge that I'm trying to overcome … and I'm enjoying it," Mickelson insisted. "I'm having fun with it. It's an exciting opportunity, and every year it comes around I get excited to try to conquer that opportunity."
Mickelson's mostly uneven 2015, with two top-five finishes that include his first runner-up at the Masters, wouldn't necessarily predict a sharp effort at Chambers. But he did two things to raise his prospects: Mickelson closed the St. Jude Classic with a 65 on Sunday and, unlike most of the top pros, made a pre-tournament reconnaissance visit to quirky Chambers, about which he continues to rave.
"A wonderful golf course. It's playing and set up much like we're used to at the British Open," said the player who before his Open Championship triumph had posted only two top-10s in his previous 19 tries in the major.
What makes Chambers Bay most inviting for Mickelson is that some of the fairways are as wide as football fields (he ranks a poor 153rd on tour in driving accuracy), and there is the requisite short-game finesse required, for which Mickelson has few rivals. It also isn't expected to be very windy this week, an advantage for a high-ball hitter like Lefty.
"You don't have to hit perfect golf shots around here to be able to score and get around it," Mickelson said.
Mickelson has even come up with what he might calls his "Chambers" club, a 60-degree wedge from which he basically shaved off the bottom to give it no bounce on the firm fescue.
Among those lauding Mickelson's chances is Greg Norman, the two-time British Open winner who will be in the TV booth for Fox. Norman was at Mickelson's side for Tuesday's practice round, talking course strategy with the player and his caddie, Jim "Bones" Mackay.
"This golf course is good for him; it fits his eye," Norman said. "I love the way he's swinging the club.
"The biggest thing for him is staying calm. He's going to feel [the excitement] for sure. It's about him managing his own expectations."
Shut out of winning the U.S. Open and Masters, Norman knows all about unrealized goals. Mickelson has a record six runner-ups in the U.S. Open, the last coming two years ago at Merion. Mickelson has said numerous times that not winning the national championship would be an immense disappointment.
"I've always been somebody, ever since I was a kid, who got motivated by failure," Mickelson said. "Some people get discouraged by that, and it almost pushed them away. For me it's a motivator to continue to work harder and get over the hump."