Ross Murdoch (GBR), a 100m breaststroke silver medallist at the past two European Championships, was the unluckiest 'loser' of the day when British swimmers swam the three fastest times in the event's heats at Tollcross International Swimming Centre on Friday.
Adam Peaty (GBR), the world record holder and reigning Olympic, World and European Champion, was fastest into the evening semi finals by a long way, as he finished in 57.89 seconds.
The two other British swimmers were James Wilby (GBR) and Scotsman Murdoch, who went in the fourth heat. Wilby triumphed by two hundredths of a second, finishing in 59.12s.
Murdoch was third fastest of the other competitors but because no more than two swimmers from the same federation can progress from the heats, he was eliminated.
"I'm disappointed, it was utterly close," said Murdoch, who will now focus on his preferred event, the 200m. "It was the fastest heat I've ever done by a country mile. It's been three years since I was near a time like that."
In fact, it was the second fastest long-course 100m of Murdoch's career, after the 59.09s he swam in 2015.
Russia also had three men fast enough for the semi finals but only two went through, leaving the 18th-placed Swede, Erik Persson, who was 1.80 seconds slower than Murdoch, with a route into the next round.
Wilby, who beat Murdoch in the Commonwealth Games 200m final in April, said: "The back end is my strength and that was a good back end for the start of the week.
"We knew the first race was going to be pretty tough with only two going through out of three. The competition (between the Britons) is something I'll always remember. It's tough but we're all really good friends."