With an interesting weekend of William Hill Scottish Cup action in store, we look at five things to watch out for in the fourth round fixtures… Friday Night Lights The action kicks off tonight in Paisley as St Mirren host Partick Thistle in the first of this season’s William Hill Scottish Cup fourth round ties. Thistle, who are on a good run of form in the Scottish Premiership, will be seen as favourites against a St Mirren team who have struggled in this season’s Championship. However, new Buddies’ boss Alex Rae will be hoping to build on last week’s Refrewshire derby win over Greenock Morton. The holders begin their defence All 12 Scottish Premiership sides enter the tournament at this stage, including last season’s William Hill Scottish Cup winners Inverness Caledonian Thistle. The Caley Jags have not quite replicated their successes of last season, when they finished third in the league, but a Highland derby victory over Ross County may signal a turn in their fortunes. A terrific contest in store at Tynecastle Since their 5-1 drubbing of Hibernian in the 2012 William Hill Scottish Cup Final, the draws have not been kind to Hearts. Indeed, since that day at Hampden the Jam Tarts have failed to score a goal, losing 1-0 to Hibernian in 2012/13 and back-to-back defeats to Celtic in successive years. This season they take on Aberdeen, currently 2nd in the Scottish Premiership, in the Saturday teatime kick-off, live on BBC One Scotland. Potential giant-killings League 1 side Airdrieonians will fancy their chances of an upset in their William Hill Scottish Cup fourth round tie at home to Dundee United. Mixu Paatelainen’s team are bottom of the Premiership, 11 points adrift of 11th placed Kilmarnock. Hamilton Accies also face a tricky trip down to Annan Athletic of League 2, while Celtic face Stranraer live on Sky Sports on Sunday. William Hill Scottish Cup fourth round (Fixtures are a 3pm kick-off on Saturday unless stated) St. Johnstone v Kilmarnock Dunfermline Athletic v Ross County Stirling Albion v Inverness Caledonian Thistle Linlithgow Rose v Forfar Athletic (Saturday, 1:30pm) Dundee v Falkirk Livingston v Greenock Morton Dumbarton v Queen of the South East Kilbride v Lothian Thistle Hutchison Vale Motherwell v Cove Rangers Heart of Midlothian v Aberdeen Airdrieonians v Dundee United Stranraer v Celtic (Sunday, 3:15pm) Rangers v Cowdenbeath (Sunday, 1pm) St Mirren v Partick Thistle (Friday, 7:45pm) Annan Athletic v Hamilton Academical Raith Rovers v Hibernian