Perth-fect warm-up for Harrison ahead of 100k Championships
The race comprised 21 laps of 1.48k around North Inch Park and incorporated the Scottish National Championships.
Starting out at a similar pace to the one she is proposing to run at the European 100k Championships, Harrison was three minutes down on Kate Jenkins and Hannah Davey after eight of the 21 laps.
However, Jenkins and Davey started to pay for their early pace and Harrison moved into the lead just past half-way.
Passing the marathon distance in 3:04:55, the 41-year-old picked up her pace and ran her fastest split in the final mile to finish in 3:41:56 and go top of the 2013 UK rankings.
She lapped all the other runners except Jenkins, who was exactly 11 minutes behind.
Harrison said: “I felt comfortable throughout the race and was delighted to run the second half three minutes faster than the first.”