Can Lefty put inquiry behind him?

There's a new No. 1 in the world and one of the best-known golfers on the planet is under investigation for possible insider trading violations. Just another ho-hum week in the world of golf.

And did we mention a 22-year-old notched his first PGA Tour victory in one of the year's most prestigious tournaments?

Our scribes dive into those topics and more in the latest edition of Four-Ball.

1. Fact or fiction: The insider-trading investigation that has ensnared Phil Mickelson will hurt his chances to win the U.S. Open.

Michael Collins, ESPN.com senior golf analyst: Fact. As much pressure as Phil Mickelson already has trying to complete the career grand slam, now he's going to wonder if an FBI agent is waiting for him at the turn or when he finishes. How do you play your best golf in that situation? You don't.

Farrell Evans, ESPN.com senior golf writer: Fiction. Mickelson is a pro and if he is completely innocent of the allegations, as he attests, he will be able to have acute focus on winning his first U.S. Open to complete the career grand slam.

Bob Harig, ESPN.com senior golf writer: Fiction. Phil has dealt with numerous distractions over the years, including his wife's health, and still prospered on the golf course. This will be no different. He's clearly got issues to work on inside the ropes, however.

Kevin Maguire, ESPN.com senior golf editor: Fiction. Mickelson isn't a 20-something kid who will have trouble staying on the task at hand when the U.S. Open comes around in a couple of weeks. Granted, he'd probably prefer to have this headache off his plate, but once he pegs it in Round 1 at Pinehurst No. 2, I fully expect him to contend for the title with the goal of finishing off the career Grand Slam.

2. How long do you expect Stacy Lewis to stay at No. 1?

Collins: Until the Women's U.S. Open when teenager Lydia Ko takes over.

Evans: Lewis is the most complete player on the LPGA Tour. At 29, she has at least another six years to dominate the women's game.

Harig: Given the way she's been playing all year -- and now with two victories -- she seems poised for a lengthy stay atop the world rankings.

Maguire: It might not be long in consecutive weeks considering how close Inbee Park and Lydia Ko are, but expect Lewis to spend the majority of 2014 -- and beyond -- in the top spot. The American had a taste of the top ranking last year and learned what it takes to hold on to it.

3. What impressed you most about Hideki Matsuyama's first PGA Tour victory?

Collins: His poise. Even when he made mistakes coming down the stretch, he outwardly didn't get overly emotional in either direction. The driver break on the 18th tee I blame on an already weakened shaft. He didn't slam it down that hard.

Evans: Since Matsuyama took low amateur honors at the 2011 Masters, I have been impressed with his calm demeanor and the deliberate, unrushed way that he swings the golf club. Through an up and down final round that included his driver head coming off at the 72nd hole, to his first PGA Tour playoff, the 22-year-old Matsuyama handled himself like a seasoned pro.

Harig: His birdie putt on the 18th hole of regulation, especially given the fact he did it all four days. A double-bogey at the 16th and a bogey at the 17th had him reeling, but he bounced back to make birdie on No. 18 and force a playoff that he then won with an impressive par on the same hole.

Maguire: In an already extremely stressful situation trying to notch his first win on U.S. soil, the 22-year-old snapped his driver on the 72nd hole, but didn't lose his cool. He still made birdie on the hole and then parred No. 18 in the playoff to pull off the victory. Many players, especially young ones such as Matsuyama, might not have stayed so even-keeled, but the kid from Japan handled himself well.

4. Of all the wild things that happened Sunday during the final round of the Memorial, which was the biggest stunner?

Collins: Kevin Na hitting it in the water off the tee in the playoff. He had plenty of time to warm up on the range for that tee shot, especially after a week of driving above you're average. (He's at 62 percent for the year and was 73 percent for the week.) For him to make that swing after having time to prep for it was a bit out of left field.

Evans: Bubba Watson's wild driver off the 15th tee out of bounds into a Muirfield Village neighborhood was the wildest moment of the final round at the Memorial. Here you have the reigning Masters champion with Jack Nicklaus' tournament under control and he hits a driver on a reachable par-5 where he could have hit a 4-wood. The episode just proved that the same things that make Bubba great -- his free-spirit, almost savant approach to the game and prodigious length -- are the same qualities that will sometimes costs him tournaments.

Harig: Matsuyama breaking his driver on the 18th tee. He did so in anger, after hitting a tee shot that actually turned out to be OK and bounced back into the fairway. It meant he wouldn't have use of the club, and only because the round ended would he have been able to replace it with another driver. But he went with 3-wood off the tee in the playoff -- not a good one -- still managing to make par and win.

Maguire: Take a look at Hideki Matsuyama's scorecard on his final six holes of regulation: birdie, bogey, birdie. double-bogey, bogey, birdie (to force a playoff.) That's one roller-coaster of a finish. The fact that he kept it together while the wheels were coming off and on shows he can handle the ups and downs of PGA Tour pressure.