Olympic silver medallist Jamieson is seeking a medal upgrade at next month's World Championships in Barcelona and certainly looks in red-hot form.
And there were no signs of his recent tender injury at the British Gas Swimming Championships as clocked 2:07.78.
"I'm delighted with the time but hopefully my injuries have healed up and I can get back to doing some really training over the next month," he said.
"I had a partial tear in my bicep tendon about four or five weeks ago and just been a pain as doesn’t heal as a muscular injury does.
"I've not been able to lift weights, so I've lost a bit of strength and weight as a result of that.
"The positive is I don’t feel like I am 100 per cent here but still managed to pull something out and sometimes it goes that way.
"So the plan is now to get some good prep in and I should be able to go faster in Barcelona."
Robbie Renwick claimed his second national gold with a 200m freestyle win - and insists he is ready to surprise a few of world swimming's stars in Spain.
"The time was pretty good as well so I can’t complain, I’ve only been rested for nine days," he said.
"I’m really excited for Barcelona now. The World Championships are what it is all about this season, I think I can surprise myself there."
Elsewhere, Hannah Miley advanced sixth quickest into the 200m medley final and admitted adding to her success over 400m - in which she claimed an eighth consecutive national title - will not be easy.
"It’s getting harder every year, there’s a lot of youngsters coming through nipping on my heels," she said.
"I’m not going down without a fight but I think that titles probably definitely going to be gone."