The Scot started the day two shots off the lead at four under having managed to finish his first round on a weather-delayed opening day but he ended it at 11 under, leading the way from overnight leader Tapio Pulkkanen.
The Finn fired a 67 to sit a shot clear of local favourite Adrian Otaegui, who carded a 66.
Jamieson has been no stranger to the top of a leaderboard on the DP World Tour in 2022, leading for three rounds in the Rolex Series at the Abu Dhabi HSBC Championship and also after 18 holes at the Ras Al Khaimah Championship presented by Phoenix Capital.
His fine form has brought him two top tens but he is still searching for an elusive second DP World Tour victory after winning the Nelson Mandela Championship presented by ISPS HANDA in December 2012, and is looking to improve his weekend play.
"It was another great day," he said. "Yesterday after five weeks off I was a little unsure about what I was going to get but it was a solid day and today was even better.
"Pretty similar but I holed one or two more putts and managed to chip in on 15 and then hole a putt from off the green on 18.
"This year I seem to be coming out of the gates very well, I've had some good starts so far and I think it's easier to play the golf course the first two rounds because you're not necessarily playing other people at that point.
It gets tougher as the tournament goes on so hopefully I can do a good job of continuing to play the golf course
"It gets tougher as the tournament goes on so hopefully I can do a good job of continuing to play the golf course."
Jamieson birdied the 11th but gave the shot straight back before making a hat-trick of gains from the 14th with the help of a chip-in on the 15th.
An eagle putt from distance on the fringe of the 18th green put him into a share of the lead and he holed from five feet on the first before draining a 20-footer on the seventh to establish a cushion.
Pulkkanen birdied the sixth but gave the shot back on the eighth before another gain on the ninth kickstarted his round.
Further birdies followed on the 11th and 13th and while he bogeyed the 15th, a smart up-and-down on the last gave him the clubhouse lead from the morning starters.
Otaegui birded the first and then holed a 40-footer on the second but gave both those shots back as he four-putted the fifth for a double-bogey.
Further gains on the eighth and ninth saw him turn in 32 and he made a 15-footer on the 11th but once again his fine momentum was stalled by a bogey on the 13th before he took advantage of the par-five 16th and last.
A monster birdie putt on the 16th was the highlight of Mansell's 64, a score matched by Nemecz, who was bogey-free.
Højgaard recovered from a bogey on the 11th with four birdies in a 67, while co-overnight-leader Veerman dropped shots on the tenth and 11th but fought back for a 69.
Law carded a rollercoaster 68 containing an eagle, four birdies, two bogeys and a double which left him a shot ahead of England's Ashley Chesters, South African Hennie du Plessis and Dane Thorbjørn Olesen.