Dave I'm a scouser and have lived in and around north london since 1986, including islington, so I know the area well.Finsbury Park has a few decent pubs around the tube station including the Worlds End, where you can watch the game and pick up birds to boot. You'll also find a decent crowd at the famous cock next to highbury & islington tube. Head north from finsbury park and you'll find crouch end, which is a bit posher and the Kings Head pub has big screens.
There are plenty of places to avoid around there, but they'll be obvious to you. Enjoy your time in London, just down go south of the river.