The European 800 metres champion, 23, has been under orders from coach Terrence Mahon to seize the initiative after being admonished for consistently running wide.
And with a superb turn of speed that saw the Scot run the closing lap in less than 57 seconds, she crushed a field that included world-class rivals Charlene Lipsey and Rose Mary Alanza to win in 1 min and 59.72 secs, the second-quickest time of her career.
Jamaica's Kaliese Spencer, Eilidh Child's main rival for 400m hurdles gold in Glasgow, extended her winning streak to six races in a time of 55.08. However Meghan Beesley, the British No.2, withdrew from the Games yesterday due to a fractured foot.
Meanwhile, in Loughborough, Scotland's 4x400m relay figureheads underlined they are finding their form with Jamie Bowie snaring victory in a season's best of 46.18 seconds. Team-mate Greg Louden was second in his race in a personal best of 46.96 while Hampden-bound high jumper Rachael MacKenzie was second on countback to Victoria Dronsfield after both leapt 1.76m.
Elsewhere, world 400m champion Christine Ohuruogu claimed the qualifying time she needed to book her place at next month's European Championships with a run of 51.66 seconds that tops the UK rankings.