Recap of the day
Morning wave: A stunning back-nine burst of six birdies in as many holes saw Zach Johnson emerge from the scrum of early par-breakers, carding a 7-under-par 63 that set the clubhouse target. Peter Malnati was not too far behind and was another to torch the back nine (he made four birdies and one eagle). Beau Hossler and Matt Jones added 65s to lie tied third after the morning starters had completed their laps.
Afternoon wave: "Wave" felt about right, as Jordan Spieth, Rory McIlroy and Justin Thomas thrashed the course, bearing down on the top of the leaderboard like a rising wall of water. The surf broke first for Thomas, who made a late bogey to complete a 66, whilst Spieth and McIlroy hurtled onwards. An 18th-hole error cost McIlroy, who carded 6-under 64, but Spieth eventually joined Johnson on 7-under 63.
Leaderboard: -7 Zach Johnson, Jordan Spieth, -6 Peter Malnati, Rory McIlroy, Brian Harman, -5 Matt Jones, Beau Hossler, Paul Casey
Notables: -4 Jason Day, Bryson DeChambeau, Justin Thomas, -2 Brooks Koepka, level Bubba Watson, +2 Patrick Reed, +4 Marc Leishman
Revised outright betting: Spieth 10/3, McIlroy 4/1, Thomas 9/1, Casey 12/1, Day 14/1, Johnson 14/1, Harman 16/1
Friday weather forecast
In theory a beautiful day: sunny, temperatures peaking in the high 70s, little chance of rain and nothing more than a cooling breeze.
The Leaders - how they performed
Zach Johnson (63) - Neat enough to the turn with a pair of birdie conversions at four and five (a 32'2" putt at the former, a chip-in at the latter). The stunning back nine blitz saw him convert 60'2" of putts in the six holes, but he then three-stabbed from 24'3" on the 17th.
Jordan Spieth (63) - Five laps completed for the World No. 5 at TPC River Highlands and he's yet to do anything other than lead the field (alone or shared). He also holed from a bunker (on the par-5 sixth for eagle), a neat little repeat of the shot that won him the title last year.
Peter Malnati (64) - Nothing to see here as he approached the back nine, then hold on to your hats. He holed from a bunker for birdie at 11, missed a 10'0" eagle try at the 13th but tapped in for birdie, smashed his tee shot at the short par-4 15th to 3'9" and drained it, then dropped 17'3" and 26'3" birdie conversions at 16 and 17.
Rory McIlroy (64) - Said on Wednesday: "If I can improve my consistency level, just get that up a little bit, I'll give myself plenty more chances this year." Shot 67-73-70-64 here last year so same story. Off to a good start, but can he steer clear of a lapse?
Brian Harman (64) - Only found half the fairways, but had a tap-in eagle-3 at the sixth, two kick-in birdies on the back nine, and then holed a 21- and 42-foot birdie conversions on 16 and 18.
Fate of the favorites
Rory McIlroy (64) - landed 17 greens in regulation in his second (and final) round at last week's U.S. Open and repeated the trick Thursday. Ten of his 17 greens found left him with a putt of inside 15 feet.
Jordan Spieth (63) - He found 12 (of 14) fairways and 15 greens in regulation, but the X Factor? He holed putts. Seven of them in the three- to 21-foot range, six of those for par breakers.
Brooks Koepka (68) - A cosy par to open (at the tenth) and then four birdies on the trot. Easy this game, right? Well, he added two more par breakers on the front nine, but there were four bogeys too, the last a three-putt from 5'11".
Justin Thomas (66) - Found only 5 fairways, one of those misses found water, another a tough fairway bunker and he didn't help himself by missing a 2'7" putt on his 17th hole (the eighth). Only three back however.
Jason Day (66) - A career low first lap of the course (breaking his previous best of 67) and bodes well because he averages 67.86 for rounds two through four.
Zach Johnson (63): "I've felt great about my driver for the last year and a half. Two years ago my stats were not good from an accuracy standpoint. It's gotten a lot better. Fundamentally I've kind of gotten back to where I was to some degree. This isn't going to blow you guys away, but I'm hitting the ball much further than I ever have. So I've actually had to introduce another wedge. I've always had three wedges, I've got four, just because of my variance in my yardages now."
Peter Malnati (64): "This is one of my favorite courses on TOUR. I love it. It doesn't surprise me to see that Zach Johnson's name is pretty high too. I bet he likes it. It's super fun to play this golf course."
Brooks Koepka (68): "I'm still kind of going on adrenaline, but I'll be honest, I'm dead right now. I think it showed kind of coming in. Just exhausted. Still playing good, but I just ran out of gas. I'm exhausted mentally. I'm excited to go home and nap."
Rory McIlroy (64): "I'm trying to get back to the way I swung it in, sort of in 2010, 2011. It's sort of hard because my body has changed quite a bit since then and the feelings I have. What was I doing? What was I thinking about? What was the focus on the swing? Just trying to rack your brain to recreate feelings that you had back then. That's basically what I did over the weekend. I got a feeling that really sort of resonated with me, brought me back to a time when I was swinging it really well, and just sort of went with that feeling."
Justin Thomas (66): "I was just in a weird mood today. I couldn't really get into it. I slept for a while last night and I kind of had a hard time getting out of that grogginess."
Jordan Spieth (63): "Putter was great. The last two events I missed the cut, and I actually putted really well, beat the field by at least a shot. It's just I put so much time into putting that my ball striking fell off."
Road to victory at River Highlands
2017 Jordan Spieth – R1: 1st, R2: 1st, R3: 1st
2016 Russell Knox – R1: 9th, R2: 5th, R3: 2nd
2015 Bubba Watson – R1: 1st, R2: 1st, R3: 2nd
2014 Kevin Streelman – R1: 61st, R2: 39th, R3: 7th
2013 Ken Duke – R1: 48th, R2: 32nd, R3: 6th
Notes: Streelman and Duke made strong comebacks from rough starts and it's typical of this event, where it's always possible for someone to throw in a low score. In all, ten of the last 20 winners were outside the top ten after 18 holes and six of those were T23 or lower.
Fate of the 18-hole leaders at River Highlands - where did they finish?
2017 Jordan Spieth - winner
2016 Jerry Kelly - 2nd, Vaughn Taylor - 38th, Andrew Loupe - MC
2015 Bubba Watson - 1st
2014 Brendan Steele - 5th
2013 Charley Hoffman - 7th
Notes: Loupe is far from the only recent early pace-setter to do a Rodney Pampling (the Australian who led the 1999 Open Championship after 18 holes and missed the cut). Loupe shot 64-76 in 2016, Jim Renner went 63-74 in 2011 to follow suit, whilst in 2012 David Mathis logged 64-73-74 to fall foul of the second cut.
Focus on - Padraig Harrington
You think maybe the Irishman likes TPC River Highlands? Thursday's first round 66 equalled his low score of the PGA TOUR season. If that feels familiar, it's because 12 months ago his round-one 66 here was his joint low lap of the 2017 season. 2016 and his third round 65? You guessed it, once again, his joint low score of the campaign. 2015?! You might not believe this, but same again: a first-round 66 this time (in the States at least; he did peg a 65 over The Old Course in The Open). In fact you've got to go back all the way to 2014 for the last season he didn't turn in his joint low lap of the year in Cromwell, Connecticut, and the reason for that? It wasn't on his schedule!
Focus on - Beau Hossler
The 23-year-old (T6 after a 65) doesn't hang around. He made his U.S. Open debut at 16 and a year later his first-round 70 in the same event had him T7. On his Web.com debut a first-lap 64 tied the lead in the Panama Championship, his regular PGA TOUR debut witnessed a Thursday 67 at Torrey Pines (T3), and his first appearance in this event 12 months ago started with a 66 for T6. And this year he's maintained the habit of making quick starts. This is his 17th active week of 2018 and the seventh time he has ended 18 holes ranked in the top ten (and third on the trot).
Focus on - Smylie Kaufman
This is a tough one. The 26-year-old finished T4 in the Sanderson Farms Championship early in the season, then four missed cuts followed before he was T69 in the CareerBuilder Challenge. Oh, for a run of just four lost weekends now. His latest run (not including the pairs event in New Orleans) is at 12 and yet there seemed to be a tiny ray of hope when he shot 77-67 in the Byron Nelson Championship, the latter a first sub-70 effort since January. Alas, he's since gone 75-78, 79-75 and opened this week with an 80 which could have been worse: He was +10 through 13 holes. The good news? He closed with a 146-yard approach to 5'6" and converted the birdie. He's down, but not out.