5 things to look for on Friday at the U.S. Open

Rickie Fowler lit up Erin Hills on Thursday. (Getty Images)

There was an air of mystery on Thursday morning as the U.S. Open began at first-time host Erin Hills in rural Wisconsin. Though it had previously hosted a pair of USGA championships, it had never held an Open. At 7,845 yards, Thursday’s setup was the longest in major championship history.

However, thanks to substantial pre-championship rain, including Wednesday evening, Erin Hills lacked some of the fire it needed to defend itself against the onslaught of some of the world’s best. Rickie Fowler tied a U.S. Open record with a 7-under 65 that matched the lowest first round against par in championship history. Several unknowns popped up on the leaderboard, while the likes of Brooks Koepka and Paul Casey also posted strong rounds in the mid 60s.

With Round 1 in the books at Erin Hills, here are five things to look forward to on Friday.

It’s going to get tougher. A U.S. Open record 42 players finished under par on Thursday, beating the prior mark by three. That sounds shocking given the length on the scorecard, but Erin Hills lacks a defense without wind and being firm enough to punish inaccurate shots. Barring pop-up storms overnight, this course should be firmer and tougher on Friday.

The top 10 has to play better. On Thursday, just two players in the world top 10 broke par: leader Rickie Fowler (-7) and Sergio Garcia (-2). With the best players in the world back against the ropes and facing a potential missed cut, expect many of these players to rally on a tougher layout and get to the weekend. It’s a long, uphill climb back into contention, but these players know there’s a lot of tournament left.

The fescue will continue to be prominent. Going into the week, few figured the 2-foot-tall deep fescue would be a factor for many players. Nope. It loomed large, swallowing poor and overly aggressive tee shots. Some of the players who were bit by the tall stuff on Thursday may choose to lay back more with fairway woods off the tee.

The 36-hole scoring record is in play. With enough players at 5 under or better after Day 1, there’s an outside chance the U.S. Open 36-hole scoring record is in play. Rory McIlroy was at 11-under 131 in 2011. Rickie Fowler is a 68 away from tying the mark.

A lefty near the top of the ‘board. The U.S. Open is the only major never won by a left-handed player. Brian Harman just happens to be lefty and two off the lead heading into Friday. While the Wells Fargo Championship winner is considered a long shot to win the title on Sunday, his hanging around could give hope to southpaws everywhere, including Phil Mickelson.

Ryan Ballengee is a Yahoo Sports contributor. Find him on Facebook and Twitter.