On a brutal day of Saturday scoring in windy, firm conditions, Zalatoris, 25, posted a brilliant 67 to move to 4-under par.
England's Fitzpatrick, 27, had moved one shot ahead after a birdie at 17 but he handed it back on 18 to card a very solid round of 68.
Zalatoris and Fitzpatrick have both been playing some exceptional golf on the PGA Tour of late but neither has yet tasted victory on the circuit.
They will both be looking to set that record straight on Sunday.
Zalatoris lost out in a playoff to Justin Thomas at the US PGA Championship last month, while Fitzpatrick has notched three top-10 finishes in his last four starts.
But it's far from a two-horse race at the US Open, especially with a number of star names hot on their heels.
Defending champion Jon Rahm is just one shot back on 3-under par, while World No.1 Scottie Scheffler is two back alongside Adam Hadwin and Keegan Bradley.
Scheffler had moved to 6-under par earlier in the round but the wheels quickly came off him thereafter with a double-bogey at 11 followed by bogeys at 12, 13 and 14.
The reigning Masters champion did recover a shot back on 17 though and he remains in contention for a fifth title of the season.
Rory McIlroy struggled for much of the day but he is still in the hunt for a first major in eight years at 1-under par alongside an in-form Sam Burns.
Keep up to date with all the latest updates and scores with our LIVE commentary of Round 3 of the US Open...
Right, everyone has teed off now.
Joel Dahmen, wearing his trusty bucket hat, hits a confident tee shot at the first hole. And Collin Morikawa matches him.
Just ahead of them Jon Rahm opens with a par. Hayden Buckley makes bogey.
Rory McIlroy and Aaron Wise are in a spot of bother.
Both leave themselves lengthy putts for par after finding the rough at the par-3 second.
McIlroy, in fairness, was in a dreadful lie. His chipped second did its level best to try and dribble down to the cup but it stopped well short.
And would you believe it! His par attempt stops right in the jaws. How did that not drop?! His ball came to rest on the edge of the cup.
Bogey.
McIroy is 3-under now and two back.
That was a pretty bad opening tee shot from McIlroy.
But he manages to hack his second over the back of the green and chips to a distance to give him an easy par putt.
Jon Rahm and Hayden Buckley have just teed off behind them.
This is what the top-10 looks like at the moment...
Collin Morikawa, Joel Dahmen -5
Hayden Buckley, Jon Rahm, Rory McIlroy, Aaron Wise -4
Will Zalatoris, Sam Burns, Scottie Scheffler, Nick Hardy, Beau Hossler -3
Scheffler gave up his birdie at No.1 by dropping a shot at the par-3 2nd.
Scottie Scheffler is just very good at golf...
That's the start he wanted!
Scottie Scheffler (-4) opens with a at the 1st.
Watch his entire round as part of our featured groups coverage presented by @AmericanExpress: https://t.co/tRFshSi5Xepic.twitter.com/E1l4y8nrXt
— U.S. Open (USGA) (@usopengolf) June 18, 2022
Also, Rory McIlroy is now underway alongside Aaron Wise.
But it's a poor opening tee shot from the Northern Irishman.
Big fore shout left...
Sam Burns makes birdie at No.3.
His 20-foot birdie putt curls perfectly into the cup and he moves to 3-under.
Matthew Fitzpatrick has to settle for par and stays at 1-under.
Reports are emerging that the DP World Tour has made the decision not to allow the LIV Golf players tee it up at the Genesis Scottish Open.
Why is this big news?
Because for the first time in its history it is co-sanctioned by the PGA Tour.
Is DP World Tour chief executive Keith Pelley strengthening the strategic alliance?
We're told that the conditions are difficult right now.
And they look it.
But that doesn't matter for Scottie Scheffler.
He drains a long birdie putt at No.1 and the Masters champion is one shot back and 4-under par for the tournament.
Remember these shirts, anyone?
Justin Rose has already done a throwback to that Justin Leonard celebration this week.
Oh man. Early favorite for fans of the day. pic.twitter.com/Jzdi4dIdsU
— Monday Q Info (@acaseofthegolf1) June 18, 2022
Ireland's Seamus Power moves into red figures for the day with an eagle at No. 8.
He's level par alongside Dustin Johnson, Cameron Tringale and earler leader MJ Daffue.
Watch:
Seamus Power with an to get into red figures @usopengolf. pic.twitter.com/5DiYquA6yn
— Golf Central (@GolfCentral) June 18, 2022
Zalatoris has an early test on No. 6.
He's given himself a 15-foot look for par at the par-3 and he drains it right into the heart of the cup.
He's made two birdies in six holes and hasn't dropped a shot yet.
Zalatoris is only now two strokes off the lead at 3-under.
Matthew Fitzpatrick represents England's best hope in this year's US Open.
He's just got his round underway alongside the talented young American and Scottie Scheffler's room mate Sam Burns.
He's safely on the green in two at the first but leaves himself a tester for par to start his day.
It's barely been mentioned, but Fitzy won the 2013 US Amateur Championship here.
Perhaps they should drop that into the coverage. Just a thought.
Joel Dahmen shares the lead with Jon Rahm at 5-under par.
He is ready:
Time to roll #BuckethatBrigade! #GiveMeAGoodNumberGenopic.twitter.com/zhrlfbCuQl
— Joel Dahmen (@Joel_Dahmen) June 18, 2022
Justin Thomas' sheer honesty may have cost him a shot here early in Round 3.
He split the fairway at No. 4 but was probably more than a little bit annoyed to see his ball nestled right next to a drain.
JT hit the shot anyway and fatted his approach into the bunker. It led to a bogey.
"That's what p****s me off because so many other people would lie about being able to hit that, but it's just like I'm not going to hit it, like I'm just trying to be a good f****** person... f****** bulls***"
Brooks Koepka claimed his confidence in majors perhaps means some of his peers aren't big fans of his.
The newly-married man moved into the picture at the US Open after a solid 67 on Friday but he has had a nightmare start today, making three bogeys in a row from No.2.
He manages to stop the bleeding at No.5, the par-5, by stroking in a short-ish birdie putt to move back to 3-over par.
England's Callum Tarren has been the surprise package this week.
He's a PGA Tour rookie and had an interesting time of earning his full playing rights.
His wife was due to give birth at the back end of last season. Tarren was given the green light to earn his Tour card and he did just that at the Korn Ferry Tour finals.
It's been a mixed bag so far this season but he's slowly trending in the right direction.
And now he's here.
Unfortunately, it's a three-putt bogey at No. 1 to see him back to level par.
Scottie Scheffler is on the range warming up.
He'll tee off at 8.01pm BST / 3.01pm ET alongside Matthew NeSmith.
Scheffler told the media on Friday evening he likes being the "under-the-radar" guy.
Will he make a move this afternoon?
Here are some of the key remaining tee times:
Matt Fitzpatrick / Adam Hadwin 2.39pm ET
Matthew NeSmith / Scottie Scheffler 3.01pm ET
Aaron Wise / Rory McIlroy 3.23pm ET
Jon Rahm / Hayden Buckley 3.34pm ET
And as I type this, Jordan Spieth has just found a birdie on No. 13 to move back to 2-over par for the championship.
Is he out of it? It's only gonna get harder.
Oh goodness me. Hideki Matsuyama has just bladed his second shot from the fescue on the fifth hole.
His golf ball cannons off the flagstick and races back into the greenside bunker.
The former Masters champion is at 1-over for the championship and will have work to do to keep it that way.
Justin Thomas misses a short left-to-right slider for birdie at No. 5.
Things are not going his way today.
Thomas got himself into a spot of bother of No.4 when his ball came to rest next to a drain.
He didn't get a ruling from an official and hit the ball anyway. It led to a bogey.
He'll stay at 2-over par for the championship for now.
JT on not getting relief here and hitting a bad approach because of it: "That's what pisses me off is that so many other people would lie about being able to hit that." pic.twitter.com/NVZpYRGeNi
— Kyle Porter (@KylePorterCBS) June 18, 2022
We've seen this story before. @WillZalatoris is in the mix at another major. #USOpenpic.twitter.com/fEbEc5ikO0
— U.S. Open (USGA) (@usopengolf) June 18, 2022
Will Zalatoris is already on the move.
He rolls in a nice birdie putt on No.3, the par-3 measuring at 217 yards.
Zalatoris, last season's Rookie of the Year, takes his score to 2-under for the championship alongside Sam Burns, Matthew Fitzpatrick and Adam Hadwin.
That group are currently T-13.
Good evening folks. Ben here to take you through the next few hours of coverage of this 122nd US Open at Brookline.
Thanks to Andy for the updates so far.
As you join me, Matthew Fitzpatrick has arrived on the range ahead of his third round.
Fitzy is at 2-under par for the championship and looking to finally get that win in the United States.
Also, can we just appreciate the outfit that Patrick Reed is wearing today?
Incredible look. pic.twitter.com/oxswZ9PNo5
— Kyle Porter (@KylePorterCBS) June 18, 2022
Here's how the leaderboard looks ahead of the leading groups teeing off in the next hour:
-5 C Morikawa, J Dahmen (US)
-4 R McIlroy (NI), J Rahm (Spa), H Buckley, B Hossler, A Wise (US)
-3 S Scheffler, M NeSmith, P Rodgers, B Harman, N Hardy (US)
-2 S Burns (US), M Fitzpatrick (Eng), A Hadwin (Can)
Good news for the leading groups as the wind appears to have died down a little.
We are seeing a few more birdies out there now.
Five players are currently in the red on the course.
Leading groups heading out in two hours' time.
