The findings at Firrhill High will reinforce the clamour for further curricular change and a quickening of the pace of learning in secondary.
Her Majesty's Inspectorate has long advocated more challenging work in S1 and S2 and Firrhill is one of the first to prove that pupils can cope with ease and enjoy the experience.
Sixty of the more able pupils in S2 this year are following the same maths course as their peers in S3. Testing last December showed that most were performing as well while the top third in each year group were performing almost identically.
A second round of assessment is likely to confirm these results. Patricia Cairns, Firhill's headteacher, said: "They are eating up the work and enjoying it. It's the pace of learning and the demands you put on them and this is coming through loud and clear."
She added: "We take four leisurely years to get to Standard grade and the students are getting hit in S5."
It would be less stressful taking Highers in fifth year if more in-depth work could be carried out earlier. Pupil motivation should be increased, she believes.
Setting by ability groups in maths is said to push up attainment, along with the whole-class, more direct teaching methods advocated by HMI.
All S2 pupils in August will begin the Standard grade course in maths. They are currently following a revised S1 maths course.
The city council describes the developments as "encouraging", but said it was "premature" to draw conclusions.