Taking up where he left off with a closing 66 in the Saudi International at the start of the month, the Lothians star carded a four-under-par 68 at Al Mouj in Muscat.
The effort, which contained an eagle and six birdies, left Gallacher in a tie for fifth, two shots behind the clubhouse leader, Italian Guido Migliozzi, with a handful of players still to complete their round.
"It was a mixed bag," said Gallacher, a four-time European Tour winner, of an effort that was illuminated by a 3 at the long third - his 12th hole.
"But I think the good outweighed the bad. I played pretty good, just hit a bad shot at the wrong time to take a double."
It came at the par-4 17th - his eighth - to take him back to level-par, but he said of that setback: "You can do that round here.
"It's a brilliant golf course, one of the best we play all year, but you get penalised if you hit a bad shot and that's what happened."
After missing the cut in both Abu Dhabi and Dubai at the start of his 2020 campaign, Gallacher handed himself a massive boost with that strong finish in Saudi Arabia.
"I just wanted to keep that going," admitted the 45-year-old, who is gearing up to defend his Hero Indian Open title in the middle of next month. "I've done that today and I'm delighted with with my start, especially after a three-week lay-off.
"I like this golf course with the wind. It's a bit like Scotland in that it's firm and fiery. It's as close as you'll get to playing a links course abroad. It kind of suits your eye if you like shaping shots.
"I've done pretty well here in the past, finishing in the top 10 the first year the first year we were here (in 2018) then getting a bit unlucky with the weather last year (when he missed the cut following a second-round 81 in brutal conditions).
"It's supposed to get windy at the weekend, but I'll keep plugging away and see what happens."
Migliozzi, a two-time winner as a rookie last season, carded six birdies in a bogey-free effort, which earned him a one-shot lead over a group that includes 2018 Aberdeen Standard Investments Scottish Open champion Brandon Stone.
"This is a tricky course because the greens are tough and tight," said Migliozzi. "There are a lot of things which need your attention like the wind and the release of the ball.
"You can play each hole in a few different styles, but it’s really cool and all the players are really happy to play here.”
Alongside Stone on five-under are Korean Taehee Lee and Rasmus Hojgaard, the young Norwegian rookie who won the AfrAsia Bank Mauritius Open earlier in the season.
Grant Forrest was next best among the Scots with a two-under 70, which left him sitting in a tie for 25th.
Among those set for an early-morning return to complete their rounds are Migliozzi's two compatriots, Lorenzo Gagli and Edoardo Molinari.
They were reinstated in the event this morning after being withdrawn 24 hours earlier due to coronavirus concerns.
Gagli sits three off the lead on three-under with a hole to play, with former Scottish Open champion Molnari also going well on two-under.