It had been MacIntyre who’d enjoyed playing with major winners Ernie Els and Charl Schwartzel in South Africa last month before being in the same group as 2017 Race to Dubai champion Tommy Fleetwood in the final round in Abu Dhabi a fortnight ago.
Now Johnston is set to test himself against one of the game’s top players after hitting the halfway mark alongside DeChambeau, the world No 5 and winner of the Omega Dubai Desert Classic last weekend, on four-under-par.
Johnston carded a second-round 66 to earn his position just outside the top 10 in the $3.2m event on a day when world No 3 Dustin Johnston stormed into a three-shot lead on the back of a brilliant 61.
“I knew it was close,” said the Scottish Johnson of his five-birdie effort. “As golfers, you can tell when your game is getting there even though you might not be scoring as well as you’d like.
“I’m happy with four under today and a lot to build on heading into weekend so I’m looking forward to it.”
The 25-year-old from Dumfries had missed four cuts in a row coming into this event but believes he is starting to find his feet on the European Tour.
“It is starting to sink in a bit more,” he added. “This is work for me now and I’m here to compete against these guys as opposed to early days when you are playing in European Tour events and you think too much about the fact you are playing in events with these guys.
“It’s a case of, ‘right, it’s time to show my stuff and see what I can do up against these guys’.”
Johnston sparked his lowest round on the European Tour with a run of three birdies in a row from the short third, suffered his only blip at the eighth then picked up shots at the 12th and 18th.
“I hit a really nice 6-iron into two feet at the third, a tough par 3, and that got the momentum going. My only bogey was a three-putt on eight and that was a bit of a shame. But I’m delighted with today and now I’m looking forward to the weekend.”
At the par-5 18th, Johnston’s drive was just off the fairway, forcing him to lay up short of the water guarding the green, but he finished in style with a superb up and down.
“That was nice as I’ve been working a lot on my wedges and it’s nice to see it starting to pay off,” he admitted.
“It is nice to make the cut. But it’s only the halfway stage. It’s a nice building block to hopefully go on and have a nice weekend.”
This is just the second event that the former Scottish Stroke Play champion has had Ken Herring, one of the most experienced caddies on the European circuit, on his bag.
“It’s been really good,” said Johnston of the partnership so far. “You can see the experience he’s got. He’s really good, especially when it comes to giving me clarity over certain shots.
“He’s been out here for 30-odd years and he’s always telling stories that help keep me relaxed. That’s helping taking my mind off things at certain times but he’s also good at getting you focused and back into the shot.”
MacIntyre, who is on one-under after rounds of 69-70, has now made five cuts in his first six events on the circuit at just 22.
“I played great today. I hit so many good putts that didn’t go in. It’s like riding against a wave at the moment on the greens - but it’s going to turn, I know it will.”
After dropping a shot at the par-3 16th to drop to level-par for the tournament, MacIntyre thought he needed to eagle the last, a par 5 measuring more than 600 yards, to make it to the weekend.
“I hit the best drive I could possbly hit and was left with a 5-wood, which is not the most trustworthy club in my bag,” he said.
“But, when I need it to perform, it seems to do the business for me and I found the middle of the green.
“It was the same club and a similar distance at the last in the Foshan Open (where he made an eagle to get into a play-off in a Challenge Tour event there towards the end of last season.
“I actually thought it was a bit closer, but I gave myself a chance and that’s all you can ask for. Level-par out there when you are not holing as many putts as you could be is good.”
Looking to kick on over the weekend, the former Scottish Amateur champion added: “I believe in every part of my game. You’ve got to when you are out here. I’ve got to get the putter going. We had a couple of events last year when we got it going and we were right in about it.
“It’s about knuckling down, grafting and hopefully it will turn sooner rather than later.”
There were early exits for the other six Scots in the field, with Stephen Gallacher coming closest to joining his two young compatriots.
The three-time European Tour winner covered his last 12 holes in two-under but, on one-over, he agonisingly missed out by a shot.
“It’s back to the drawing board,” he said, having struggled with his driving in particular in both Abu Dhabi and Dubai. “I can’t control the ball in the wind at the moment.”
Three-under at the start of the day, Scott Jamieson was on course to progress comfortably after opening with eight pars but then dropped three shots in four holes before taking two more bogeys late on.
That left him having to settle for a 75 for two-over, a shot ahead of both David Drysdale and Richie Ramsay.
For Drysdale, a third missed cut in the Desert Swing was a blow to his hopes of being in the top 10 in the Race to Dubai after next week’s Vic Open, which would earn him a place in next month’s WGC-Mexico Championship.
Two-under starting out, Ramsay’s hopes of starting his 2019 campaign with three straight cuts were effectively scuppered by a triple-bogey 8 at the 18th - his ninth.
David Law and Grant Forrest also missed out on seven and eight-over respectively, with all the Scots to bow out early playing in the tougher afternoon conditions on day two.