After Round 1 at the AT&T Pebble Beach Pro-Am, Kevin Streelman and Beau Hossler share the lead at 7 under. Streelman shot a 7-under 65 at the Spyglass Hill course, and Hossler fired the same 7-under 65 number at Pebble Beach (golfers play three different courses over the first three rounds before Round 4 at Pebble).

They have a lot of chasers, though. Matt Kuchar is T3 after the first day, and then the dominoes start to fall. Dustin Johnson is T6 and just two back. Patrick Cantlay is also 5 under and T6. Rory McIlroy is T16 after a 4-under 68. Jon Rahm is on that same 4-under number. Huge stars chasing a youngster in Hossler and a vet in Streelman makes for a solid final three rounds.

The first day's worth of play was as lengthy but as beautiful as well probably thought it would be. There were fireworks early and often -- Cantlay started birdie-ace-birdie (!) -- and several fun celebrity sightings on Thursday, including Aaron Rodgers running in long putts and liberally tossing out fist pumps. 

Here are five takeaways on Round 1 of the 2018 Pebble Beach Pro-Am.

1. Dustin Johnson might be unstoppable: He led early in the day, and he never left the leaderboard throughout. D.J. had six birdies and just a single bogey in his 5-under 67 at Spyglass Hill as he played alongside future (?) father-in-law Wayne Gretzky. Johnson, it struck me today, has somehow become the most consistent entity on the PGA Tour. I pretty much know what I'm getting every time out, and if he wavers at all from that then it's a surprise. After six top-5 finishes at this event -- including two wins -- he's the guy to beat with 54 holes left (Vegas also has him as the +350 favorite).

2. Rory McIlroy did Rory McIlroy things (so did his dad): In his first appearance on the PGA Tour in 2018, McIlroy birdied all four par 5s he played and threw in two more at par 4s for good measure. He shot a 4-under 68 at Spyglass Hill, which was enough to get him into the top 20 after the first day. 

But Rory's game might have been less interesting than his father Gerry's on Thursday. Watch his pops walk after this putt while it's still two feet from the cup! Apples and trees.

Those two don't lead the amateur side of the event, though. That lead also belongs to Streelman and his partner Larry Fitzgerald, who combined to fire a 14-under 58 on Thursday. They're up three with a long way to go.

3. Difference in scoring on the three courses: According to my math (admittedly a bit dicey sometimes), here's how the three courses played on average on Thursday.

  • Pebble Beach: 71.3
  • Spyglass Hill: 71.2
  • Monterrey Peninsula: 69.6

Streelman and Hossler both shot their 65s on the two harder courses. The best number at Monterrey was a 66 from Aaron Wise. But that score was only 3.6 strokes better than the field average there, whereas Hossler and Streelman were both about 6.25 strokes better than the averages on their courses. It's not something to get super fired up after 18 holes, but it's something to keep an eye on as the leaders go to Monterrey over the next few days (Johnson and McIlroy both played Spyglass, too).

4. Spieth's putting woes continued: Playing alongside Johnson, Spieth shot an even-par 72 at Spyglass. The issue was once again his putter. His career average for putts per round is around 28, but he took 32 again on Thursday (the norm for him so far this year). 

Golfweek correctly pointed out that his putting has almost been lousy on the West Coast swing, and I won't be concerned unless this lasts up until the Masters. Spieth, for his part, doesn't sound too concerned either. He said the issue is that he has his hands too far forward and is hitting the ball into the turf.

"The idea is to just stop thinking, just putt, and not having to worry about things," Spieth told reporters this week. "That's not the reality for a little going forward, until my setup over the putter, I'm seeing my lines and I'm set up toward those lines."

5. Mickelson hung in: Lefty has now played four weeks in a row so the four-time winner of this event could have taken a pass for being exhausted. But after playing the first 10 holes in 2 over, he battled back and shot a 31 coming home at Spyglass to get into real contention after 18 holes. I don't know that he can last the full four days given how much golf he's played, but a weekend with him in contention is always a thrill. Even more so considering he missed out on a playoff at this event just two years ago.