Drysdale and Johnston both missed the cut in the Magical Kenya Open after opening with rounds of 72 and 73 respectively last Thursday at Karen Country Club in Nairobi.
It was much more like it, though, in the first circuit of the Kenya Savannah Classic at the same venue as Drysdale carded a six-under-par 65, one less than Johnston’s equally-impressive morning effort.
Drysdale sits joint-fifth, one off the lead, which Harding, winner of the first leg on Sunday, shares with three others, with Johnston also handily-placed in a share of 13th spot.
On another low-scoring day, Drysdale made his score by racing to the turn in 29, having opened with four straight birdies from the tenth then adding further gains at the 15th, 16th and 18th.
The newly-turned 46-year-old had some of the wind taken out of his sails by a double-bogey 6 at the third before getting one of those shots back with a birdie-3 at the seventh.
“It’s a decent start,” said the Borderer. “I played great on the back nine, my front nine, to be out in 29.
“I then got unlucky at the third hole, where my drive clipped a tree and bounced right, leaving me with no shot, really, and ended up making a double-bogey.
“That was a shame and, though I had a few chances coming in, the greens are much more grainy and slower on the front nine and I mis-read a few putts.”
For Johnston, an effort that contained six birdies and a solitary bogey, which came at the last, was his best start since carding a 61 to set up a top-15 finish in the Portugal Masters last September.
“It was actually really good today,” said the 28-year-old Dumfries man, who lost his full main tour card after finishing 148th in the Race to Dubai in 2019.
“I went out and played 18 holes yesterday. I thought I’d get out on the course and try and free myself up a little bit.
“I decided to play two holes a bit more aggressive and I played great. I think I hit 17 greens and was four-under in regulation.
“It was a really good ball-striking day until the last, where I made bogey, which was a bit bittersweet, but, if someone had said I’d shoot five-under, I would have taken it."
Johnston, who won the 2018 Kazakhstan Open as he graduated from the Challenge Tour along with Bob MacIntyre, Grant Forrest and Connor Syme, added: “I get a little bit too hard on myself.
"Sometimes I play to avoid bad holes instead of trying to play good holes and I think I did the latter really well today.”
Harding, who is now 28-under-par for five rounds on this course, set the pace along with Dutchman Joost Luiten, Spaniard Alejandro Canizares and Clement Sordet from France.
Calum Hill, who tied for eighth in the first event, picked up three shots in his last four holes for a 67, one less than Craig Howie, but Syme, third on Sunday after a closing 64, had to settle for a par-71.