With three places available in each discipline for Glasgow 2014 at the Scottish Gas National Championships, Murdoch claimed the GB record in 27.28sec in the morning heats and then equalled it in the final. Fellow medallists Mark Tully (27.73) and Joseph Welstead (27.83) were also within the Games' time.
"My goal now is to make it into Team Scotland in all three breaststroke events," said the 20-year-old who swam for GB at last summer's World Championships.
Last night's effort was a real appetiser for his head-to-head clash tonight with Michael Jamieson, the Olympic seilver medallist from the London Oympics. "It's a big relief to get the time and win the 50m," added Murdoch. "I nearly broke the British record in Belgium earlier this year so it was at the back of my mind. But I was surprised to do it in the heats."
Hannah Miley, the Commonwealth Games Champion, was in a class of her own in the 400m individual medley and her time of 4:35.48 ensured that the 2010 champion in New Delhi will be back to defend in Glasgow.
"It was a great swim but I know there is a lot more in the tank," said the 24-year-old. "I'll now put in a a lot of hard work and put in the training time so that I go even faster in the summer."
In the 20m butterfly, the top two of Cameron Brodie ((1.58.18) and Lewis Smith (1:58.37) both gained the Games qualification time and Kathleen Dawson (29.21sec) also earmarked her place in Team Scotland with victory in the 50m backstroke.
The final event of the evening was the 1500m freestyle - and top two Stephen Milne (15.18.90) and Craig Hamilton (15.20.16) both qualified for the Games.
Hampered by a back injury, veteran Caitlin McClatchey still managed to win 200m freestyle in 1:59.38. Winner of the 200m and 400m freestyle at the 2006 Commonwealths in Melbourne, the three-time Olympian is desperate to make it to a third Games. "Everything considered, I'm pleased," said the 28-year-old who is studying for a Masters degree in Performance Psychology at Edinburgh University. "I know once the back improves I can go a lot, lot faster."
Robbie Renwick, who hopes to stage a successful defence of the 200m freestyle at Glasgow 2014, won the 100m event but was clearly unimpressed with a 50.13sec time that left him well adrift of the qualification mark.
"It was simply not good enough," admitted the two-time Olympian. "I've got to find some form and I'm hoping for the best in the 200m." The 25-year-old swims at Tollcross with City of Glasgow and he will be favourite to add the 400m title tonight and his favourite 200m on Sunday.