The first round of the second FedEx Cup Playoff event is a wrap at TPC Boston, and Justin Rose is your 18-hole leader after firing the only 6-under 65 in the field on Day 1. Rose kept his card clean all day and made five birdies in the process for the 65. 

His closing act was his best. After going to the 15th hole sitting at 3 under on the day, Rose birdied three of his last four (including the last two) for the 66 and a one-stroke lead over Russell Knox and Abraham Ancer and a two-stroke lead over Chris Kirk, Beau Hossler, Keegan Bradley and Gary Woodland.

It's the latest in what has been about a year's worth of great play for Rose. Of his last 25 events worldwide starting at the end of 2017, Rose has finished in the top 10 a remarkable 18 times (including four wins). There's even more at stake this week than another top 10 or even a FedEx Cup Playoff win. 

Rose could feasibly become the No. 1-ranked player in the world with a victory in Boston. He would be the fourth golfer from England to hold the spot. Luke Donald, Nick Faldo and Lee Westwood did as well.

Rose has been a monster so far this year from tee to green (11th on the PGA Tour), and his putting has improved immensely (19th). Both areas shined again on Friday as he gained strokes with the flat stick and finished No. 2 in the field from tee to green.

This event is certainly not over or anywhere close to it, but when you have a horse like Rose galloping out in front after 18 holes, things can get a little tighter for the rest of the leaderboard. The Englishman will try to put a little distance between him and everyone else in Saturday's Round 2 as he searches for what would be his fifth win worldwide in the last 12 months and a possible ascension to the top spot in the world of golf.

Here are three more takeaways from Round 1 at the Dell Technologies Championship.

1. Beau Hossler, future star: When evaluating players for future potential, I like to find guys who have quirky stats or nuances that are keeping them from success. Hossler qualifies. After firing a 4-under 67 in Round 1 at TPC Boston, Justin Ray noted that Hossler now has 34 rounds after which he's been in the top 10 on the leaderboard. Thirty-four! At some point that's going to translate to a win (or many of them).

2. Phil Mickelson, still dancing: Lefty is still cutting up both on and off the course this week, but he's not playing all that well in the process. Mickelson shot a 1-over 72, which was the same as his good friend Tiger Woods' 1-over 71. Who knows if the fatigue of a long season is finally starting to get to these guys, but it will be something to monitor as this event wears (and these playoffs wear) on.

3. Billy Horschel, gone: After his top 10 finish at The Northern Trust, Horschel moved to No. 18 in the FedEx Cup rankings. Unfortunately for him, he played the first nine holes in 5-over 41 and had to eject with an illness. He will likely still be inside the top 30 in the rankings next week with a solid chance of making it to East Lake, where he won in 2014.

CBS Sports was with you the entire way Friday updating this story live with the latest scores, highlights and analysis from Round 1. If you are unable to view the updates below, please click here.

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