The 17-year-old Bishopbriggs Academy pupil held off fellow Scot Holly McGill, from Edinburgh, to win the 200 metres backstroke crown at last week’s British Swimming Championships at the Ponds Forge International Sports Centre in Sheffield.
And as an added bonus Shanahan also secured a consideration time for the Commonwealth Games, which take place in Birmingham this summer.
Shanahan and McGill were fastest qualifiers in the heats but Loughborough University’s Honey Osrin set the early pace in the final, turning first at halfway.
However Shanahan and McGill came through in the final 50 metres with Shanahan taking the win in 2:11.25, ahead of McGill (2:11.84) and Osrin (2:12.12).
The City of Glasgow Swim Team member told Scottish Swimming: “I knew I had to put on a good race with the girls because I knew they'd come back strong. I could see all the girls coming for me. That last 5m, I tried to hold my ground and push as hard as I could to the wall.”
Shahanan added another medal, and Commonwealth Games consideration time, the following day when she took bronze in the 200 metres individual medley.
The teenager admitted she was pleased with her performances after illness affected her in the lead up to the championships.
She said: “It’s gone better than I expected. I was a bit unwell. So to be doing these times I’m really happy.”