SPRINGFIELD, NJ - What a difference a day makes.

Thursday’s round of 32, 16 scores

Friday’s quarterfinal matchups
(Quarterfinal winners advance to the afternoon semifinals, starting at 12:18 p.m. EDT)

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After the top nine and 13 of the first 14 seeds advanced to the round of 32 Wednesday, chaos ensued on Thursday at the 71st U.S. Junior Amateur Championship on another gorgeous day on Baltusrol Golf Club’s Upper Course in Springfield Thursday.

Below is a summary of what happened (per USGA) in an unpredictable match play Thursday:

Michael Thorbjornsen will head into the quarterfinals with a slight disadvantage, but one that just about any of his fellow competitors would take in a heartbeat. The 16-year-old from Wellesley, Mass., hasn’t seen the final two holes of the Upper Course since Round 2 of stroke play, having dispatched each of his three match-play opponents in 16 or fewer holes. His sharp game was on full display Thursday, rolling into the quarterfinals in his USGA championship debut with a pair of impressive victories. The 2016 Drive, Chip & Putt national champion never trailed throughout the day, defeating Nate Stember, 7 and 5, in the Round of 32, before winning four of his first five holes in his Round-of-16 match against Ryan Smith before holding on for a 3-and-2 triumph.

Thorbjornsen, who credited the sharpness of his wedge game with his dominant performance on Thursday morning, didn’t have it as easy in the afternoon, but was able to ride the early momentum generated on the first hole, where he erased early troubles with a chip-in for par, while Smith three-putted from 30 feet for bogey. Thorbjornsen  was 1 up on the 298-yard 14th hole when he laid up with a 5-iron off the tee and hit a wedge to 8 feet before burying the putt. A Smith bogey on the par-3 15th put Thorbjornsen 3 up before he closed things out on the next hole.

“I kind of got away with it a little bit. I wasn't playing as well as I did this morning, but I still managed to hit some good shots and pretty much just grind through it,” he said. “I’m definitely going to stick to the same game plan. On the range tomorrow morning, I’ll just make sure that I'm hitting my drive straight, because that's going to be my setup for the whole day tomorrow.”

In contrast to Thorbjornsen, University of Texas-bound Cole Hammer, this year’s U.S. Amateur Four-Ball co-champion with fellow U.S. Junior Amateur competitor Garrett Barber, found himself with his back against the wall much of Thursday afternoon. After a 4-and-3 win over Kaiwen Liu, Hammer lost the first two holes of his Round-of-16 match against Trent Phillips and was 3 down through 10 holes before birdies on holes 11 and 14 closed the gap. Phillips was still in the driver’s seat, and had putts to win on Nos. 17 and 18 from 12 feet and 6 feet, but missed them both, and then bogeyed the 19th hole to send Hammer to his first Junior Amateur quarterfinal in four tries.

“This is as far as I've ever been, trust me, I knew that coming down the stretch. I was like, man, I really don't want to lose in the Round of 16 three years in a row,” said Hammer. “The way we both played coming down the stretch was pretty impressive, and I'm going to remember this for a long time, that's for sure.”

Shuai Ming (Ben) Wong, of Hong Kong China, enjoyed the largest margin of victory in the Round of 16, losing the second hole of his match to Jacob Bridgeman before winning eight of his next nine holes and ultimately prevailing, 7 and 6. That was likely a welcome respite from his Round-of-32 match in the morning, which took him 19 holes to dispatch Jolo Timothy Magcalayo, of the Philippines. In the round of 32, Bridgeman had upended stroke-play medalist and 15-year-old Kelly Chinn of Great Falls, Va. in 20 holes.

In addition to Hammer and Phillips, only one other match reached the 18th hole on Thursday afternoon, with Dothan, Ala.-native Thomas Ponder winning the last two to defeat Connor Creasy, 1 up, in a contest he never led until the end.

Baltusrol Bits: None of the quarterfinalists have advanced this far in the championship previously. Among the group, Cole Hammer has made the deepest runs, advancing to the Round of 16 in 2016 and 2017, while Joe Highsmith bowed out in the Round of 32 the last two years. The only 2017 quarterfinalist to advance to the Round of 16 was Ryan Smith, who lost to Michael Thorbjornsen, 3 and 2. … Friday morning’s match between Hammer and Shuai Ming (Ben) Wong pits co-champions of the last two U.S. Amateur Four-Ball Championships. Wong won the Four-Ball title in 2017 with Frankie Capan at Pinehurst No. 2. … Cameron Sisk and Alejandro Madariaga are the only two players remaining who have not trailed in any of their matches this week. … Fellow Inman, S.C., residents Jacob Bridgeman and Trent Phillips would have played one another in the quarterfinals on Friday, but both lost in the Round of 16. Bridgeman lost to Wong, 7 and 6, while Phillips was defeated by Hammer in 19 holes. … After the first two days of tournament opening stroke-play, Baltusrol’s Lower Course was back open to its members on Wednesday. … After each match tees off on the first hole, legendary USGA starter John Reis leaves the golfers with some advice: “Make it memorable gentlemen!”

Admission: FREE, FREE, FREE – come on out!

FS1: FS1 will have live coverage of Friday’s semifinals and Saturday’s championship match. Broadcast times are as follows (All times EDT): Friday: 2-4 p.m.; Saturday: 1-4 p.m.

Springfield Social: Fans can follow the action throughout the championship and join the conversation by following the USGA on Twitter, Facebook and Instagram, and by using the hashtag #USJuniorAm.

Friday’s Weather (provided by weather.com): Sunny skies. High 83F. Winds SE at 10 to 15 mph. Humidity: 51%. UV Index: 9 of 10. Sunrise: 5:43 a.m., Sunset: 8:23 p.m. EDT.