CIYMS entered the game in search of a second consecutive win after their defeat of Cooke in 2013, while Grosvenor were looking to cause an upset that would give them bragging rights over the club they share facilities with on the Belmont Road.
That meant Grosvenor earned bragging rights over the outfit they share a clubhouse with on the Belmont Road.
Grosvenor's physical approach presented outhalf Peter Davison with an early penalty but he sent his kick well off target. But his side did open the scoring in the 11th minute when David Egner collected a loose ball and outsripped the covering defence. Davison's skewed conversion attempt left Grosvenor with a 5-0 advantage.
CIYMS hit back with a few strong runs, with number 8 Mark Scott and scrumhalf Michael Wilson to the fore. Indeed it was Wilson who got their first try in the 24th minute when he dummied and dived over from close range. Michael McComb, who had missed an earlier penalty, made no mistake with the conversion for a 5-7 lead.
That lasted just five minutes as inside centre Jamie Meaklim powered over after good work by his tight forwards and scrumhalf Neil Adams. Davison again missed the conversion but he made amends with the last action of the half, notching a penalty from the touchline to bring the half time score to 13-7.
The same player had a well struck penalty at the beginning of the second half but it fell just short. Grosvenor continued to frustrate their neighbours, with Paul Karayiannis making a couple of crucial turnovers.
Edgar then produced a moment of magic to bag his second try. Having caught the ball on his own 10 metre line, he proceeded burst through the middle of the first line of defence before picking off a couple more defenders on route to touching down under the posts. Davison added the extras to extend the lead to 20-7
CIYMS were given a glimmer of hope when the ball was spun wide and Robin Brown gathered Andrew Hodgen's offload to cross in the right corner. McComb's conversion was just wide, leaving the score reading 20-12 with 15 minutes remaining.
The black and whites pushed for further scores late on but the well marshalled Grosvenor defence held firm to deny them.
Grosvenor:
15 Chris Cahoon
14 David Egner
13 Ben Coard
12 Jamie Meaklim
11 Mark Atkinson
10 Pater Davison
9 Neil Adams
8 Paul Karayiannis
7 Sam Purdon
6 Matthew Cahoon
5 James Bowman
4 Peter Dawson
3 Pearce Jamison
2 Mark Cartmill
1 Phil Hill
16 Matthew Alllen
17 Stuart Smyth
18 Jeff Mealiff
19 Jamie McMullan
20 Stephen Kirk
CIYMS
15 Robin Brown
14 Neil Wallace
13 Andrew Hodgen
12 Philip McVitty
11 Jason Gilliland
10 Michael McComb
9 Michael Wilson
8 Mark Scott
7 Scott Dowle
6 Ross Hackney
5 Stephen McReynolds
4 Patrick Aiken
3 Stuart Ferguson
2 Matt Brown
1 Gavin Woods
16 Jonathan Jordan
17 Chris Davidson
18 Richard Greenwood
19 Stephen Foster
20 Duncan Gleadhill