PGA Tour: 5 Things Learned from Phil Mickelson's Win at Pebble Beach

Phil Mickelson collected his 40th PGA Tour title on Sunday at Pebble Beach with a flawless 64 in the final round.

The four-time Major champion won the AT&T Pebble Beach National Pro-Am by two shots over South Korean Charlie Wi—coming from six shots behind to win.

In another enthralling week on the PGA Tour, it wasn't just "Lefty's" win that had people talking afterwards. There were a lot of sub-plots in California.

Let's take a look at the top-five lessons learned.

Phil Mickelson Is Still a Force to Be Reckoned with

After turning 40, a lot of golfers are immediately written off by golfing pundits who say they are too old and lack the enthusiasm to keep up with the younger golfers.

Over the years, many have disproved this theory: Vijay Singh, Steve Stricker and Jack Nicklaus (who won the Masters at 46).

Phil Mickelson could be the latest in a line of golfers who do well over 40. After a poor 2011 in which he won only once and only contended at one of the four Majors (The Open where he came in tied for second), Mickelson showed on Sunday what a great golfer he is when he is on top form.

A stunning 64 in the final round showed Mickelson at his best, and no one was going to stop him.

With the Masters less than two months away, don't rule him out to win a fourth green jacket.

Tiger Woods Is Still Struggling for Confidence

Once the greatest Sunday player ever, Tiger Woods now seems to hate them.

In his prime and at his best, Woods would destroy the rest of the field on the final day as he hunted down another trophy.

But on Sunday at Pebble Beach, he was all over the place, as he struggled to get any sort of rhythm going.

He finally shot a 75; he was outscored by 11 shots by longtime rival Phil Mickelson.

Having not won a PGA Tour event since 2009, Woods seemed distinctly nervous all round on Sunday, something many thought wasn't ever possible.

American Golf Is in a Very Healthy State

Phil Mickelson's win on Sunday means that the first six events of the 2012 PGA Tour have all been won by Americans.

That's quite an astounding stat when you consider most of the golfing media now talk of the great standard of European golf.

Admittedly, a lot of the top European golfers have yet to venture across to America, but for American golfers to notch up half a dozen wins already this season is impressive.

Behind Mickelson, 2009 US Open runner-up Ricky Barnes finished third; other Americans in the top 10 included Dustin Johnson, Kevin Na and Spencer Levin.

It will certainly be fascinating to see if the Americans can keep this run through the Northern Trust Open this week.

Padraig Harrington Is Struggling for His Best Form

Like Tiger Woods, multiple Major champion Padraig Harrington is also struggling to get over the finishing line like he used to.

The winner of The Open in 2007 and 2008 and the PGA Championship in 2008 eventually finished in a tie for seventh at Pebble Beach.

Now, that might not sound like a bad result, but at one stage Harrington looked like a real contender for the tournament but failed to show the steely determination he showed four or five years ago.

Having also failed to challenge at any of the Majors last year, Harrington now faces a real challenge to get back to his best and prove to his critics he isn't past his best.

Many Golfers Laid Down a Marker for the Masters

The tournament at Pebble Beach is traditionally where the top golfers start to lay down markers ahead of the Masters at Augusta in April.

Of course, there are many tournaments before then, and the odds at the betting shops will change significantly.

But last week in California, golfers such as Dustin Johnson and Aaron Baddeley showed their desire to start the year in a positive fashion by finishing in the top 10.

Johnson in particular must be regarded as a contender in Georgia by already gaining three top-10 Major finishes.

The biggest marker of all was Mickelson's win. He loves Augusta, and I will be stunned if he isn't challenging in the 2012 Masters.