The all-conquering Englishman carved out a 26.98-second fastest heat time after posting a Games record 26.74sec split during his 100m final victory on the Gold Coast.
Peaty has won 20 major long-course medals in just the last four years and has proved invincible since storming to gold in Glasgow in 2014.
He was matter of fact about his swim, estimating he was "60 percent" switched on.
"There's no emotional involvement there, I'm just trying to get through the heats," Peaty said.
"I'm not really taking it too seriously. I think I have been guilty of that in the last few championships. I was 60 percent engaged there so it was pretty good."
While another major title beckons for Peaty, South African Chad le Clos was fifth fastest in 100m heats as he bids for an unprecedented butterfly Games treble.
The four-time world champion has already become the first male swimmer to win three consecutive Commonwealth gold medals in the same event following Saturday's triumph in the 200m fly.
Le Clos has also taken out the 50m event and will now zero in on the 100m fly title.
Humbled to be first man in history to swim 3 consecutive races 2010/2014/2018 thanfull to everyone for the support ❤️❤️🇿🇦🇿🇦🥇🥇 pic.twitter.com/udtFb1ET7G
England's James Guy topped the charts in 53.16seconds – 0.51sec ahead of le Clos into the semi-finals.
"I think it's going to be a lot tougher to be honest, because James is a bronze medallist from last year's worlds and Grant Irvine and David Morgan are in front of their home crowd, so I'm not going to write anybody off," le Clos said.
Australia's sprint queen Cate Campbell, bidding for a third gold medal at the meet, eased through as fastest qualifier in the 100m freestyle heats.
Campbell had 0.74sec to spare over Canadian Taylor Ruck with her heat time of 54.05sec, while sister Bronte was third fastest into the semi-finals in 54.81.
"I had a little look around at the turn and saw I had some clear water so I thought, 'Alright, you can just cruise through'," said Campbell, who has also won the 50m freestyle and anchored the winning 4x100m freestyle relay.
"I'm really just taking it one step at a time. It's physically and emotionally draining, so I need to make sure I'm not getting ahead of myself."
Canada's Olympic champion Penny Oleksiak won her heat in the fourth fastest time of 54.88sec.
Canada's Kylie Masse followed up her 100m backstroke gold with the fastest time of 2:09.12 in the 200m heats.
"It is important to pat myself on the back and realise I had done well and I was proud of myself," Masse said.
"I still have a lot of races here, the 200m (backstroke), the 50m (backstroke) and the medley relay. I will get back and refocus."