Scotland's Ross Murdoch capped a very good opening day for the home nation by claiming a surprise gold in the men's 200m breaststroke.
Murdoch, 21, stormed clear of the pre-race favourite Michael Jamieson to win in a new British record time of 2:07.30.
A stunning triumph
With 50m to go, it had looked as though Jamieson, an Olympic silver medalist in the event, would have enough to stretch away from Murdoch, but the younger swimmer streaked clear in the latter stages to shock his countryman.
England's Andrew Willis claimed the bronze in a time of 2:09.87.
More Scottish success
The race capped a very good day for the hosts after Hannah Miley had earlier claimed the first gold medal in the pool, winning the 400m medley in front of a raucous Glasgow crowd.
The 24-year-old powered away from England's Aimee Willmott in the last 50m to win Commonwealth gold in a new Games record of four minutes 31.76 seconds, obliterating the time she had set in qualifying for the final.
Willmott, 21, had led all the way until the last of the eight lengths, had to settle for silver, with Keryn McMaster of Australia taking the bronze.
Further medal success for the home nations came in the freestyle events. In the men's 400m 18-year-old James Guy took bronze, while fellow Team England member Siobhan-Marie O'Connor took silver in the 200m equivalent.
Then, in the final race of the day, England's 4X100m freestyle team of Fran Halsall, Amy Smith, Siobhan-Marie O'Connor and Becki Turner claimed silver in a new British record time of 3:35.72.
Australia won the gold, dominating the field and setting a new world record in the process. Their time of 3:30.98 beat the previous mark set by the Netherlands.