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One stroke made a big difference twice this week for Patrick Cantlay. On Friday, he made a par to fall inside the cut on the number at The American Express and earn his way into the last two rounds. On Sunday, he made a 38-foot birdie putt at the last hole to take a clubhouse lead after shooting 61 on Sunday and 126 for the weekend. An hour later, Si Woo Kim would usurp him by a single stroke for his first win since the 2017 Players Championship.

The 61 from Cantlay is the round of the year thus far and will go down as one of a handful of best rounds we see in 2021 when the calendar flips 11 months from now. Cantlay gained a preposterous 9.62 strokes on the field (anything at or around 10 is round-of-the-year material), but the hole he put himself in following a 69-71 start was too much, and Kim's 64 on Sunday was good for his third career PGA Tour win.

There was drama for him as well. After playing his first 33 holes on the weekend bogey-free, Kim narrowly escaped a disastrous second shot into the par-5 16th that could have ended up in a bunker the size of a mountain (he made birdie) and then buried an 18-foot putt on the par-3 17th on Sunday to go one stroke up on Cantlay. That's where he would finish after making par at No. 18. Kim finished at 23 under to Cantlay's 22 under, just good enough to win The American Express.

"I kept watching the leaderboard. Patrick kept making birdies," Kim told Golf Channel after the victory. "I kept trying to think positive."

It's been a long and sometimes-winding road for Kim, who is both older and younger than you probably think. At 25, he's just 20 months older than wunderkind Collin Morikawa but has already played in 164 PGA Tour events -- 23 fewer than Rory McIlroy -- with wins at the Wyndham Championship and Players Championship. 

Kim has struggled with injuries off and on over the last few years, though, and he dropped well outside the top 100 in the Official World Golf Rankings at this point last year when he withdrew from this tournament with a back injury. That was shortly after firing an 87 in Round 1 with two 8s and a 9 on the card. Still, the talent level remains immense, and he found form late in the year with a pair of top 10s.

It was again on display this week as he made just two bogeys all week and none (none!) at the tougher Stadium Course. While Cantlay's 61 seemed like it should have been a winner, it also took away from the fact that Kim shot the second-best round of the final round to clip him for the event. One stroke either way often feels negligible over the course of a year or career, but as we saw with Cantlay this week and Kim this weekend, it change a tournament and sometimes a career. Grades for Kim and Cantlay: A+

Tony Finau (4th): Mixed feelings. He gained strokes against the field -- as he's done 16 of 19 times he's entered the final round in the top five -- but it was so uninspiring. Two missed putts inside of 4 feet, a water ball and zero closing kick. As my pal Kevin Van Valkenburg pointed out about Aaron Rodgers as the Packers were simultaneously taking a loss in the NFC Championship Game, your record is your record, and Finau's is not very good at this point. Grade: B

Rickie Fowler (T21): After a miserable 2020 (for him), he actually hit the ball really well in his first start of 2021. He finished top five from tee to green (although that's only on three measured rounds because one of the two courses at this tournament is not lasered). It's not where he needs (or wants) to be, but it could be a nice kick-start for him as he tries to qualify for the Masters. Shockingly, the T23 finish was his best since early August 2020, nine tournaments ago. Fowler now has no top 10s in the last 12 months. Grade: B-

Brooks Koepka (MC): We were told that this week was a warmup for the warmup for Koepka, who remains focused on major championships (and therefore next week's Farmers Insurance Open at 2021 major venue Torrey Pines). His 72-71 at The American Express resulted in his second missed cut in a row on the PGA Tour, which is actually a first for him since the start of 2017 when he missed consecutive cuts at the Genesis Open and Honda Classic. Grade: D-

Phil Mickelson (MC): Lefty said this week that he's going to consider playing PGA Tour Champions more if his start to the PGA Tour year goes poorly. It certainly started poorly as he shot 74-72 to miss the cut by six. Somehow, I ended up picking him in my one and done league this week (going to have to walk back through that thought process) even though this is his fourth missed cut in his last seven events dating back to last year's The Northern Trust. I fear the PGA Tour Champions may get much more run from Mickelson in the near future. Grade: F